Part IX — Inorganic Poisons
I Precipitated From a Hydrochloric Acid Solution by Hydric Sulphide — Precipitate Yellow or Orange. — Arsenic — Antimony — Cadmium700
1. Arsenic
§ 707. Metallic Arsenic, at. wt. 75, specific gravity of solid 5·62 to 5·96, sublimes without fusion in small quantities at 110° (230° F.) Guy. It occurs in commerce in whitish-grey, somewhat brittle, crystalline masses, and is obtained by subjecting arsenical pyrites to sublimation in earthen retorts, the arsenic being deposited in suitable receivers on sheet iron. Metallic arsenic is probably not poisonous, but may be changed by the animal fluids into soluble compounds, and then exert toxic effects—volatilised metallic arsenic is easily transformed in the presence of air into arsenious acid, and is therefore intensely poisonous.
§ 708. Arsenious Anhydride—Arsenious Acid—White Arsenic—Arsenic, As2O3 = 198; specific gravity of vapour, 13·85; specific gravity of opaque variety, 3·699; specific gravity of transparent variety, 3·7385. Composition in 100 parts, As 75·75, O 24·25; therefore one part of metallic arsenic equals 1·32 of As2O3. It is entirely volatilised at a temperature of 204·4°.
In analysis it is obtained in brilliant octahedral crystals as a sublimate on discs of glass, or within tubes, the result of heating a film of metallic arsenic with access of air. It is obtained in commerce on a very large scale from the roasting of arsenical pyrites. As thus derived, it is usually in the form of a white cake, the arsenious acid existing in two forms—an amorphous and a crystalline—the cake being generally opaque externally, whilst in the centre it is transparent. According to Kruger, this change from the crystalline to the amorphous condition is dependent upon the absorption of moisture, no alteration taking place in dry air. Both varieties of arsenious anhydride are acid to test-paper.
The solubility of arsenious acid is often a question involving chemical legal matters of great moment. Unfortunately, however, no precisely definite statement can be made on this point, the reason being that the two varieties of arsenic occur in very different proportions in different samples. Both the amorphous and crystalline varieties having very unequal solubilities, every experimenter in succession has given a different series of figures, the only agreement amid the general discrepancy being that arsenic is very sparingly soluble in water.
The statement of Taylor may, however, be accepted as very near the truth, viz., that an ounce of cold water dissolves from half a grain to a grain. According to M. L. A. Buchner,701 one part of crystalline arsenious acid dissolves after twenty-four hours’ digestion in 355 parts of water at 15°; and the amorphous, under the same condition, in 108 of water. A boiling solution of the crystalline acid, left to stand for twenty-four hours, retains one part of acid in 46 of water; a similar solution of the amorphous retains one of arsenic in 30 parts of water, i.e., 100 parts of water dissolve from 2·01 to 3·3 parts of As2O3.
Boiling water poured on the powdered substance retains in cooling a grain and a quarter to the ounce; in other words, 100 parts of water retain ·10. Lastly, arsenious acid boiled in water for an hour is dissolved in the proportion of 12 grains to the ounce, i.e., 100 parts of water retain 2·5.
K. Chodomisky702 has investigated the solubility of recrystallised arsenious acid in dilute acids, and his results are as follows:—100 c.c. of 1·32 per cent. hydrochloric acid dissolves 1·15 grm. As2O3 at 18·5°. 100 c.c. of 6 per cent. hydrochloric acid dissolves 1·27 grm. at 18·5°. 100 c.c. of pure hydrochloric acid of the ordinary commercial strength dissolves 1·45 grm. As2O3. 100 c.c. of dilute sulphuric acid at 18° dissolves about 0·54 grm.; at 18·5° from 0·65 to 0·72 grm.; and at 80° from 1·09 to 1·19 grm.
§ 709. Arsine—Arseniuretted Hydrogen, H3As.—Mol. weight, 78; vol. weight, 39; specific gravity, 2·702; weight of a litre, 3·4944 grammes; percentage composition, 95·69 As, 4·31 H; volumetric composition, 2 vol. H3As = half vol. As + 3 vol. H. A colourless inflammable gas, of a fœtid alliaceous odour, coercible into a limpid colourless liquid at a temperature of from -30° to -40°. The products of the combustion of arseniuretted hydrogen are water and arsenious acid; thus, 2H3As + 6O = 3H2O + As2O3. If supplied with air in insufficient quantity, if the flame itself be cooled by (for example) a cold porcelain plate, or if the gas pass through a tube any portion of which is heated to redness, the gas is decomposed and the metal separated. Such a decomposition may be compared to the deposit of carbon from ordinary flames, when made to play upon a cooled surface. It may also be decomposed by the electric spark,703 e.g., if the gas is passed slowly through a narrow tube 0·7 to 0·8 mm. internal diameter, provided with wires 0·5 to 0·6 mm. apart, and a small induction coil used connected with two large Bunsen’s cells, then, under these conditions, arsenic as a metal is deposited in the neighbourhood of the sparks. For the decomposition to be complete, the gas should not be delivered at a greater speed than from 10 to 15 c.c. per minute. The gas burns with a blue-white flame, which is very characteristic, and was first observed by Wackenroder. It cannot, however, be properly seen by using the ordinary apparatus of Marsh, for the flame is always coloured from the glass; but if the gas is made to stream through a platinum jet, and then ignited, the characters mentioned are very noteworthy.
Oxygen or air, and arsine, make an explosive mixture. Chlorine decomposes the gas with great energy, combining with the hydrogen, and setting free arsenic as a brown cloud; any excess of chlorine combines with the arsenic as a chloride. Sulphur, submitted to arseniuretted hydrogen, forms sulphuretted hydrogen, whilst first arsenic and then sulphide of arsenic separate. Phosphorus acts in a similar way. Arseniuretted and sulphuretted hydrogen may be evolved at ordinary temperatures without decomposition; at the boiling-point of mercury (350°) they are decomposed, sulphide of arsenic and hydrogen being formed; thus, 3H2S + 2AsH3 = As2S3 + 6H2, a reaction which is of some importance from a practical point of view. Many metals have also the property of decomposing the gas at high temperatures, and setting hydrogen free. Metallic oxides, again, in like manner combine with arsenic, and set water free, e.g., 3CuO + 2H3As = Cu3As2 + 3H2O.
Arsine acts on solutions of the noble metals like phosphuretted hydrogen, precipitating the metal and setting free arsenious acid; for example, nitrate of silver is decomposed thus—
12AgNO3 + 2H3As + 3H2O = As2O3 + 12HNO3 + 12Ag.
Vitali704 thinks the reaction is in two stages, thus:—
(1) 2AsH3 + 12AgNO3 = 2(Ag3As3AgNO3) + 6HNO3. (2) 2(Ag3As,3AgNO3) + 6H2O = 6HNO3 + 6Ag2 + 2H3AsO3.
This reaction admits of valuable practical application to the estimation of arsenic; for the precipitated silver is perfectly arsenic-free; the excess of nitrate of silver is easily got rid of by a chloride of sodium solution, and the absorption and decomposition of the gas are complete.
In cases of poisoning by arsine, the blood, when examined by the spectroscope (a process the analyst should never omit where it is possible), is of a peculiar inky colour, and the bands between D and C are melted together, and have almost vanished. Such blood, exposed to oxygen remains unaltered.
§ 710. Arsine in the Arts, &c.—In the bronzing of brass, in the desilverising of lead by zinc, and subsequent treatment of the silver zinc with hydrochloric acid, in the tinning of sheet iron, and similar processes, either from the use of acids containing arsenic as an impurity, or from the application of arsenic itself, arsine is evolved.
§ 711. Effects on Animals and Man of Breathing Arsine.—The most general effect on mammals is to produce jaundice, bloody urine, and bile. In the course of numerous experiments on dogs, Stadelmann705 found that by making them breathe a dose of arsine, which would not be immediately fatal, icterus was always produced under these circumstances, and could be always detected by the appearance of the tissues. The bile is remarkably thickened, and the theory is, that in such cases the jaundice is purely mechanical, the gall-duct being occluded by the inspissated bile. Rabbits experimented upon similarly showed increased biliary secretion, but no jaundice; while it was proved that cats are not so sensitive to arsine as either rabbits or dogs. There are not wanting instances of arsine having been breathed by man—the discoverer of the gas, Gehlen, was in fact the first victim on record. In order to discover a flaw in his apparatus he smelt strongly at the joints, and died in eight days from the effects of the inhalation.
Nine persons, workmen in a factory, were poisoned by arsine being evolved during the treatment by hydrochloric acid of silver-lead containing arsenic. Three of the nine died; their symptoms were briefly as follows:—
(1) H. K., 22 years old; his duty was to pour hydrochloric acid on the metal. Towards mid-day, after this operation, he complained of nausea, giddiness, and malaise. In the afternoon he felt an uncommon weight of the limbs, and an oppression in breathing. His fellow-workmen thought that he looked yellow. On going home he lay down and passed into a narcotic sleep. Next morning he went to his work as usual, but was not capable of doing anything; he passed bloody urine several times throughout the day, and fell into a deep sleep, from which he could scarcely be roused. On the third day after the accident, a physician called in found him in a deep sleep, with well-developed jaundice, the temperature moderately high, pulse 100. On the fifth day the jaundice diminished, but it was several months before he could resume his work.
(2) J. T., aged 19, suffered from similar symptoms after five and a half hours’ exposure to the gas. He went home, vomited, was jaundiced, and suffered from bloody urine; in six days became convalescent, but could not go to work for many months.
(3) C. E. was very little exposed, but was unwell for a few days.
(4) L. M., 37 years old, was exposed two days to the gas; he vomited, had bloody urine, passed into a narcotic sleep, and died in three days from the date of the first exposure.
(5) J. S., aged 40, was exposed for two days to the gas; the symptoms were similar to No. 4, there was suppression of urine, the catheter drawing blood only, and death in eight days.
(6) M. E., 36 years old; death in three days with similar symptoms.
(7), (8), and (9) suffered like Nos. 1 and 2, and recovered after several months.
The chief post-mortem appearance was a dirty green colour of the mucous membrane of the intestines, and congestion of the kidneys. Arsenic was detected in all parts of the body.706
Two cases are detailed by Dr. Valette in Tardieu’s Étude.707 A mistake occurred in a laboratory, by which a solution of arsenic (instead of sulphuric acid) was poured on zinc to develop hydrogen. Of the two sufferers, the one recovered after an illness of about a week or ten days, the other died at the end of twenty-eight days. The main symptoms were yellowness of skin, vomiting, bloody urine, great depression, slight diarrhœa, headache, and in the fatal case a morbiliform eruption. In a case recorded in the British Medical Journal, November 4, 1876, there were none of the usual symptoms of gastric irritation, but loss of memory of recent acts, drowsiness, and giddiness.
§ 712. The Sulphides of Arsenic.—Of the sulphides of arsenic, two only, realgar and orpiment, are of any practical importance. Realgar, As2S2 = 214; specific gravity, 3·356; composition in 100 parts, As 70·01, S 29·91; average composition of commercial product, As 75, S 25. Realgar is found native in ruby-red crystals, and is also prepared artificially by heating together 9 parts of arsenic and 4 of sulphur, or 198 parts of arsenious anhydride with 112 parts of sulphur, 2As2O3 + 7S = 2As2S2 + 3SO2. It is insoluble in water and in hydrochloric acid, but is readily dissolved by potassic disulphide, by nitric acid, and by aqua regia. It is decomposed by caustic potash, leaving undissolved a brown sediment (As12S), which contains 96·5 per cent. of arsenic. The dissolved portion is readily converted into arsine by aluminium.
§ 713. Orpiment, or Arsenic Trisulphide.—As2S3 = 246; specific gravity, 3·48; composition in 100 parts, As 60·98, S 39·02; found native in crystals, presents itself in the laboratory usually as a brilliant yellow amorphous powder, on passing sulphuretted hydrogen through an acid solution of arsenious acid or an arsenite. It is very insoluble in water (about one in a million, Fresenius), scarcely soluble in boiling concentrated hydrochloric acid, and insoluble generally in dilute acids. Red fuming nitric acid dissolves it, converting it into arsenic and sulphuric acids; ammonia and other alkaline sulphides, the alkalies themselves, alkaline carbonates, bisulphide of potassium, and aqua regia, all dissolve it readily. In the arts it is used as King’s yellow (see p. 532). Tanners also formerly employed a mixture of 90 parts of orpiment and 10 of quicklime, under the name of Rusma, as a depilatory; but the alkaline sulphides from gas-works are replacing this to a great extent.
§ 714. Haloid Arsenical Compounds.—The Chloride of Arsenic, AsCl3 = 181·5; specific gravity liquid, 0° 2·205; boiling-point 134° (273·2°F.), is a heavy, colourless, oily liquid, which has been used as an escharotic in cancerous affections (principally by quacks). In one process of detecting and estimating arsenic, the properties of this substance are utilised (see p. 575). It is immediately decomposed by water into arsenious and hydrochloric acids.
The Iodide of Arsenic (AsI3) is used occasionally in skin diseases, but is of little interest to the analyst; it is commonly seen in the form of brick-red brilliant flakes.
§ 715. Arsenic in the Arts.—The metal is used in various alloys; for example, speculum metal is made of tin, copper, and a little arsenic; white copper is an alloy of copper and arsenic; shot is composed of 1000 parts of lead mixed with 3 of arsenic; the common Britannia metal used for tea-pots, spoons, &c., often contains arsenic; and brass is bronzed with a thin film of arsenic. It was formerly much employed in the manufacture of glass, but is being gradually superseded. It is also now used to some extent in the reduction of indigo blue, and in that of nitro-benzole in the manufacture of aniline.
In cases of suspected poisoning, therefore, and the finding of arsenic in the stomach, or elsewhere, it may be set up as a defence that the arsenic was derived from shot used in the cleansing of bottles, from the bottles themselves, or from metal vessels, such as tea-pots, &c.
The arsenic in all these alloys being extremely insoluble, any solution to a poisonous extent is in the highest degree improbable. It may, however, be necessary to treat the vessels with the fluid or fluids which have been supposed to exert this prejudicial action, and test them for arsenic. The treatment should, of course, be of a severe and exhaustive character, and the fluids should be allowed to stand cold in the vessels for twenty-four hours; then the effect of a gentle heat should be studied, and, lastly, that of boiling temperatures. The analysis of the alloy itself, or of the glass, it would seldom be of value to undertake, for the crushed and finely divided substance is in a condition very different from that of the article when entire, and inferences drawn from such analytical data would be fallacious.
Arsenious anhydride is also used for the preservation of wood, and is thrown occasionally into the holds of vessels in large quantities to prevent vegetable decomposition. In India, again, a solution of arsenic is applied to the walls as a wash, in order to prevent the attacks of insects.
§ 716. Pharmaceutical, Non-officinal, and other Preparations of Arsenic.—(1) Pharmaceutical Preparations.—The Liquor arsenicalis (Fowler’s solution), or solution of arsenic of the pharmacopœia, is composed of:—
| Carbonate of Potash, | 87 grains (5·64 grms.) |
| Arsenious Acid, | 87 gra„ns(5·64 g„ms.) |
| Compound Tincture of Lavender, | 5 drachms (17·72 c.c.) |
dissolved in 1 pint (567·9 c.c.) of water; every ounce, therefore, contains 4·3 grains of arsenious acid (or 100 c.c. = ·9As2O3); the strength is therefore nearly 1 per cent.
Liquor Ammonii Arsenitis (not officinal) is made of the same strength, ammonium carbonate being substituted for potassic carbonate.
The hydrochloric solution of arsenic is simply arsenious acid dissolved in hydrochloric acid; its strength should be exactly the same as that of Fowler’s solution.
A solution of arseniate of soda708 contains the anhydrous salt in the proportion of 4 grains to the ounce (·9 in 100 c.c.) of water.
Liquor Arsenii et Hydrargyri Iodidi (Donovan’s Solution of Arsenic).—This is not officinal, but is used to some extent in skin diseases; it is a solution of the iodides of mercury and arsenic; strength about 1 per cent. of each of the iodides.
Arseniate of Iron, Fe3As2O8, is an amorphous green powder, used to some extent in medicine. It should contain 33·6 per cent. of metallic arsenic.
Clemen’s Solution.—A solution of the bromide and arseniate of potassium; strength equal to 1 per cent. arsenious acid. Officinal in U.S., France, and Norway.
Pilula Asiatica (not officinal) is composed of arsenious acid, extract of gentian, and black pepper. There is 1⁄12th of a grain (5·4 milligrams) of arsenious acid in each pill.
Dr. De Valanguis’ Solutio solventes mineralis is composed of 30 grains of As2O3 dissolved by 90 minims of HCl in 20 oz. of water; strength = 0·034 per cent. As2O3.
(2) Veterinary Arsenical Medicine.—Common veterinary preparations containing arsenic are:—A ball for worms, containing in parts—
| Calomel, | 1·3 | per cent. |
| Arsenious Acid, | 1·3 | per „ |
| Tin Filings, | 77·9 | per „ |
| Venice Turpentine,709 | 19·5 | per „ |
A common tonic ball:710—
| Arsenious Acid, | 5 to 10 grains (·324 to ·648 grm.) | |||||
| Aniseed, | 1⁄2 oz. | ( | 14 | ·1744 | grms. | ) |
| Opium, | 30 grains | ( | 1 | ·94 | gr„ | ) |
| Treacle, | q. s. | |||||
An arsenical ball, often given by grooms to horses for the purpose of improving their coats, contains in 100 parts:—
| Arsenious Acid, | 2 | ·5 | per cent. |
| Pimento, | 19 | ·2 | „ |
| Extract of Gentian, | 78 | ·3 | „ |
Another ball in use is composed of arsenic and verdigris (acetate of copper), of each 8 grains (·518 grm.); cupric sulphate, 20 grains (1·3 grm.); q. s. of linseed meal and treacle.
(3) Rat and Fly Poisons, &c.—An arsenical paste sold for rats has the following composition:—
| Arsenious Acid, | 5 | ·0 | per cent. |
| Lampblack, | ·6 | „ | |
| Wheat Flour, | 46 | ·3 | „ |
| Suet, | 46 | ·3 | „ |
| Oil of Aniseed, a small quantity. | |||
Another rat poison is composed as follows:—
| White Arsenic, | 46 | ·8 | per cent. |
| Carbonate of Baryta, | 46 | ·8 | „ |
| Rose-pink,711 | 5 | ·8 | „ |
| Oil of Aniseed, | ·2 | „ | |
| Oil of Rhodium, | ·2 | „ |
Various arsenical preparations are used to kill flies; the active principle of the brown “papier moure” is arsenious acid. A dark grey powder, which used to be sold under the name of fly-powder, consisted of metallic arsenic that had been exposed some time to the air.
Fly-water is a strong solution of arsenious acid of uncertain strength, sweetened with sugar, treacle, or honey. Another fly-poison consists of a mixture of arsenious acid, tersulphide of arsenic, treacle, and honey.
(4) Quack and other Nostrums.—The analyst may meet with several quack preparations for external use in cancer. A celebrated arsenical paste for this purpose is composed of:—
| Arsenious Acid, | 8 | per cent. |
| Cinnabar, | 70 | „ |
| Dragon’s Blood, | 22 | „ |
Frères Come’s Cancer Paste is composed of arsenious acid, 1; charcoal, 1; red mercury sulphide, 4; water, q. s.
The tasteless “ague drops” used in the fen countries are simply a solution of arsenite of potash.
Davidson’s Cancer Remedy consists, according to Dr. Paris, of equal parts of arsenious acid and powdered hemlock.
In India, arsenic given as a medicine by native practitioners, or administered as a poison, may be found coloured and impure, from having been mixed either with cow’s urine, or with the juice of leaves, &c.712
Arsenious acid is used by dentists to destroy the nervous pulp of decayed and painful teeth, about the twenty-fifth of a grain (2·5 mgrms.) being placed in the cavity. A common formula is arsenious acid, 2; sulphate of morphine, 1; creasote, q. s. to make a stiff paste. There is no record of any accident having resulted from this practice hitherto; but since the dentist seldom weighs the arsenic, it is not altogether free from danger.
(5) Pigments, &c.—King’s yellow should be As2S3, the trisulphide of arsenic or orpiment. It is frequently adulterated with 80 to 90 per cent. of arsenious acid, and in such a case is, of course, more poisonous. King’s yellow, if pure, yields to water nothing which gives any arsenical reaction.
A blue pigment, termed mineral blue, consists of about equal parts of arsenite of copper and potash, and should contain 38·7 per cent. of metallic arsenic (= to 51·084 As2O3H) and 15·6 of copper.
Schweinfurt green (Syn. Emerald-green), (CuAs2O4)3Cu(C2H3O2)2 is a cupric arsenite and acetate, and should contain 25 per cent. of copper and 58·4 per cent. of arsenious acid. In analysis, the copper in this compound is readily separated from the arsenic by first oxidising with nitric acid, and then adding to the nitric acid solution ammonia, until the blue colour remains undissolved. At this point ammonium oxalate is added in excess, the solution is first acidified by hydrochloric or nitric acid, and, on standing, the copper separates completely (or almost so) as Oxalate, the arsenic remaining in solution.
Another method is to pass SH2 to saturation, collect the sulphides on a filter, and, after washing and drying the mixed sulphides, oxidise with fuming nitric acid, evaporate to dryness, and again treat with nitric acid. The residue is fused with soda and potassic nitrate, the fused mass is dissolved in water, acidulated with nitric acid, and the copper is precipitated by potash; the solution is filtered, and in the filtrate the arsenic is precipitated as ammonio-magnesian arseniate or as trisulphide.713
Scheele’s green (CuHAsO3) is a hydrocupric arsenite, and contains 52·8 per cent. of arsenious anhydride and 33·8 per cent. of copper.
(6) External Application of Arsenic for Sheep, &c.—Many of these are simply solutions of arsenic, the solution being made by the farmer. Most of the yellow sheep-dipping compounds of commerce are made up either of impure carbonate of potash, or of soda ash, arsenic, soft soap, and sulphur. The French bain de Tessier is composed of:—
| Arsenious Acid, | 1·00 | kgrm. |
| Ferrous Sulphate, | 10·00 | „ |
| Peroxide of Iron, | 0·40 | „ |
| Gentian Powder, | 0·20 | „ |
This is to be added to 100 kgrms. of water. Another common application consists of alum and arsenic (10 or 12 to 1), dissolved in two or three hundred parts of water.
(7) Arsenical Soaps, &c.—Arsenic is used in preserving the skins of animals. One of the compounds for this purpose, known under the name of Bécoeur’s arsenical soap, has the following composition:—
| Camphor, | 3·4 | per cent. |
| Arsenic, | 20·2 | „ |
| Carbonate of Potash, | 56·2 | „ |
| Lime,714 | 20·2 | „ |
(8) Arsenical compounds used in pyrotechny:—
| Parts. | |||
| Blue fires—(1) | Realgar, | 2 | |
| Charcoal, | 3 | ||
| Potassic Chlorate, | 5 | ||
| Sulphur, | 13 | ||
| Nitrate of Baryta, | 77 | ||
| —— | |||
| (2) | Sulphur, | 40 | ·9 |
| Nitre, | 36 | ·8 | |
| Sulphide of Antimony, | 12 | ·3 | |
| Sulp„ide of Arsenic, | 5 | ||
| Charcoal, | 5 | ||
| —— | |||
| Green fires— | Metallic Arsenic, | 2 | |
| Charcoal, | 3 | ||
| Chlorate of Potash, | 5 | ||
| Sulphur, | 13 | ||
| Nitrate of Baryta, | 7 | ||
| —— | |||
| Light green fire— | Charcoal, | 1 | ·75 |
| Sulphide of Arsenic, | 1 | ·75 | |
| Sulphur, | 10 | ·50 | |
| Chlorate of Potash, | 23 | ·25 | |
| Nitrate of Baryta, | 62 | ·50 | |
| —— | |||
| White fire—(1) | Arsenious Acid, | ·76 | |
| Charcoal, | 1 | ·63 | |
| Sulphide of Antimony, | 12 | ·27 | |
| Nitrate of Potash, | 36 | ·59 | |
| Sulphur, | 48 | ·75 | |
| —— | |||
| (2) | Realgar, | 6 | ·1 |
| Sulphur, | 21 | ·2 | |
| Nitrate of Potash, | 72 | ·7 | |
§ 717. Statistics.—During the ten years 1883-92 there were registered in England and Wales 113 deaths from arsenic; of these 57, or about half, were suicidal deaths, and 5 were classed under the head of “murder”; the rest were due to accident. The age and sex distribution of persons dying from accidental or suicidal arsenical poisoning are detailed in the following table:—
DEATHS FROM ARSENIC DURING THE TEN YEARS 1883-1892.
| Accident or Negligence. | ||||||
| Ages, | 1-5 | 5-15 | 15-25 | 25-65 | 65 and above | Total |
|---|---|---|---|---|---|---|
| Males, | 1 | 4 | 3 | 23 | 6 | 37 |
| Females, | 4 | ... | 3 | 4 | 3 | 14 |
| Total, | 5 | 4 | 6 | 27 | 9 | 51 |
| Suicide. | ||||||
| Ages, | 15-25 | 25-65 | 65 and above | Total | ||
| Males, | 3 | 32 | 2 | 37 | ||
| Females, | 5 | 12 | 3 | 20 | ||
| Total, | 8 | 44 | 5 | 57 | ||
§ 718. Law Relative to the Sale of Arsenic.—By the 14th of Vict. c. 12, every person selling arsenic is bound to keep a written record of every particular relative to each transaction, such as the name, abode, and calling of the purchaser, the purpose for which the poison is required, and the quantity sold, &c. These particulars are to be signed also by the purchaser. No person (sec. 2) is allowed to sell arsenic to any one unknown to the seller, unless in the presence of a witness whom the seller is acquainted with. The arsenic sold (sec. 3) is to be mixed with soot or indigo in the proportion of half an ounce of indigo to a pound of arsenic. It, therefore, follows that the coloured substance should not contain more than 70 per cent. of arsenious acid. The Act applies to all the colourless preparations of arsenic: but it is not to affect chemists in making up prescriptions for medical men, or in supplying medical men; nor is it to affect the wholesale dealers in supplying arsenic to retail shops, &c. The penalty for conviction is £20, or less.715
§ 719. Dose.—The smallest dose of arsenic known to have proved fatal to a human being is ·16 grm. (21⁄2 grains). Farriers and grooms are in the habit of giving as much as l·3 grm. (20 grains) a day to a horse, so that the poisonous dose for this animal must be very large.
The maximum dose for the horned cattle appears to be from ·32 to ·38 grm. (5 to 6 grains); that for a dog is 16 mgrms. (1⁄4 grain), and even this may, in the smaller kinds, cause illness.
The following may be considered as dangerous doses of arsenic:—·13 grm. (2 grains) for an adult; 1·9 grm. (30 grains) for a horse; ·64 grm. (10 grains) for a cow; and 32 to 64 mgrms. (1⁄2 to 1 grain) for a dog.
§ 720. Effects of Arsenious Acid on Plants.—If the root or stem of a plant is immersed in a solution of arsenious acid, the hue of the leaves soon alters in appearance, the green colour becomes of a whitish or brownish hue, and the plant withers; the effect being very similar to that produced by hot water. The toxic action may be traced from below upwards, and analysis will detect minute quantities of arsenic in all portions of the plant.
It has, however, been shown by Gorup-Besanez,716 that if arsenious acid be mixed with earth, and plants grown in such earth, they only take up infinitesimal quantities of arsenic. Hence, in cases of cattle poisoning, any defence based upon the alleged presence of arsenic in the pasture will be more ingenious than just.
The influence of arsenical fumes as evolved from manufactories upon shrubs and trees is in general insignificant. Pines and firs, five to six years old, have been known to suffer from a disease in which there is a shedding of the leaves, the more tender herbage being at the same time affected. Whatever dangers the practice of steeping corn intended for seed in a solution of arsenious acid, as a preventive of “smut,” may possess, it does not appear to influence deleteriously the growth of the future plant.
Superphosphate of manure is frequently rich in arsenic. Dr. Edmund Davy asserts that plants to which such manure is applied take up arsenic in their tissues, and M. Andonard has made a similar statement. Tuson717 has also undertaken some experiments, which confirm Andonard and Davy’s researches. The bearing of this with relation to the detection of arsenic in the stomachs of the herbivora needs no comment.
§ 721. Effects on Animal Life—Animalcules.—All infusoria and forms of animalcule-life hitherto observed perish rapidly if a minute quantity of arsenious acid is dissolved in the water in which they exist.
Insects.—The common arsenical fly-papers afford numerous opportunities for observing the action of arsenic on ordinary flies; within a few minutes (five to ten after taking the poison into their digestive organs) they fall, apparently from paralysis of the wings, and die. Spiders and all insects into which the poison has been introduced exhibit a similar sudden death. It is said that in the neighbourhood of arsenical manufactories there is much destruction among bees and other forms of insect life.
Annelids.—If arsenious acid is applied to the external surface of worms or leeches, the part which it touches perishes first, and life is extinguished successively in the others. If a wound is made first, and the arsenious acid then applied to it, the effects are only intensified and hastened. There is always noticed an augmentation of the excretions; the vermicular movements are at first made more lively, they then become languid, and death is very gradual.
Birds.—The symptoms with birds are somewhat different, and vary according to the form in which the poison is administered, viz., whether as a vapour or in solution. In several experiments made by Eulenberg on pigeons, the birds were secured under glass shades, and exposed to the vapour of metallic arsenic vaporised by heat. It is scarcely necessary to remark that in operating in this way, the poisoning was not by metallic arsenic vapour, but by that of arsenious acid. One of these experiments may be cited:—A pigeon was made to breathe an atmosphere charged with vapour from the volatilisation of metallic arsenic. The bird was immediately restless; in thirty minutes it vomited repeatedly, and the nasal apertures were noticed to be moist; after a little while, the bird, still breathing the arsenious acid atmosphere, was much distressed, shook its head repeatedly, and yawned; in fifty minutes the respiration was laboured, and in fifty-nine minutes there was much vomiting. On removing the bird, after it had been exposed an hour to the vapour (·16 grm. of metallic arsenic having been evaporated in all), it rapidly recovered.
Six days after, the pigeon was again exposed in the same way to the vapour, but this time ·56 grm. of metallic arsenic was volatilised. In fifteen minutes there was retching, followed by vomiting. On taking it out after an hour it remained very quiet, ate nothing, and often puffed itself out; the breathing was normal, movements free, but it had unusual thirst. On the second and third day the excretions were frequent and fluid; the cardiac pulsations were slowed, and the bird was disinclined to move. On the fourth day it continued in one place, puffing itself out; towards evening the respirations slowed, the beak gaping at every inspiration. On attempting flight, the wings fluttered and the bird fell on its head. After this it lay on its side, with slow, laboured respiration, the heart-beats scarcely to be felt, and death took place without convulsions, and very quietly. On examining the organs after death, the brain and spinal cord were very bloodless; there were ecchymoses in the lungs; but little else characteristic. The experiment quoted has a direct bearing upon the breathing of arsenical dust; as, for example, that which floats in the air of a room papered with an easily detached arsenical pigment. Other experiments on birds generally have shown that the symptoms produced by arsenious acid in solution, or in the solid form, in a dose insufficient to destroy life, are languor, loss of appetite, and the voidance of large quantities of liquid excreta like verdigris. With fatal doses, the bird remains quiet; there are fluid, sometimes bloody, excretions; spasmodic movements of the pharynx, anti-peristaltic contraction of the œsophagus, vomiting, general trembling of the body, thirst, erection of the feathers, and laboured respiration. The bird becomes very feeble, and the scene mostly closes with insensibility and convulsions.
Mammals, such as cats, dogs, &c., suffer from symptoms fairly identical with those observed in man; but the nervous symptoms (according to P. Hugo) do not predominate, while with rabbits and guinea-pigs, nervous symptoms are more marked and constant.718 There are vomiting, purging, and often convulsions and paralysis before death. It has been noticed that the muscles after death are in a great state of contraction. The slow poisoning of a dog, according to Lolliot,719 produced an erythematous eruption in the vicinity of the joints, ears, and other parts of the body; there were conjunctivitis, increased lachrymal secretion, and photophobia; the hair fell off.
§ 722. Effects of Arsenious Acid on Man.—The symptoms produced by arsenious acid vary according to the form of the poison—whether solid, vaporous, or soluble—according to the condition of bodily health of the person taking it, and according to the manner in which it is introduced into the animal economy, while they are also in no small degree modified by individual peculiarities of organisation and by habit, as, for instance, in the arsenic-eaters.
Arsenic-Eaters.—In all European countries grooms and horse-dealers are acquainted with the fact that a little arsenic given daily in the corn improves the coat, increases, probably, the assimilation of the food, and renders the horse plump and fat. On the Continent grooms have been known to put a piece of arsenic, the size of a pea, in a little oatmeal, make it into a ball, tie it up in a linen rag, and attach it to the bit; the saliva dissolves, little by little, the poison, while both the gentle irritation and physiological action excite a certain amount of salivation, and the white foam at the mouth, and the champing of the horse, are thought vastly to improve the appearance. Shot, which contains a small quantity of arsenic, have been used for the same purpose, and from half a pound to a pound of small shot has been given to horses. When a horse has been for a long time dosed with arsenic, it seems necessary to continue the practice; if this is not done, the animal rapidly loses his condition. The explanation probably is, that the arsenic stimulates the various cells and glands of the intestinal tract to a superaction, the natural termination of which is an enfeeblement of their secreting power—this especially in the absence of the stimulus. Turning from equine involuntary arsenic-eaters, we find the strange custom of arsenic-eating voluntarily pursued by the races of lower Austria and Styria, especially by those dwelling on the mountains separating Styria from Hungary. In India also (and especially in the Punjaub) the same practice prevails, and here it is often taken as an aphrodisiac. The mountaineers imagine that it increases the respiratory power, nor is there wanting some evidence to show that this is actually the fact, and medicinal doses of arsenic have been in use for some time in cases of asthma and other diseases of the chest. The arsenic-eaters begin with a very small dose, which is continued for several weeks or months, until the system gets accustomed to it. The amount is then slightly augmented until relatively large doses are taken with impunity. In one case720 it appears that a countryman, in good health, and sixty years of age, took daily 4 grains of arsenious acid, a habit which he had inherited from his father, and which he in turn bequeathed to his son.
The existence of such a custom as arsenic-eating, in its literal sense, has more than once been doubted, but all who have travelled over Styria and other places where the habit prevails have convinced themselves that the facts have not been overstated. For example, Dr. Maclagan, in company with Dr. J. T. Rutter,721 visited Styria in 1865, and having carefully weighed 5 or 6 grains of arsenic, saw these doses actually swallowed by two men. On collecting their urine, about two hours afterwards, abundant quantitative evidence of its presence was found; but in neither of the men were there the slightest symptoms of poisoning. It is obvious that the existence of such a habit might seriously complicate any inquiry into arsenical poisoning in these regions.
§ 723. Manner of Introduction of Arsenic.—Arsenious acid exerts a poisonous action, whether it is taken by the stomach, or introduced into the system by any other channel whatever. The differences in the symptoms produced by external application (as through a wound), and by swallowing arsenious acid in substance or in solution, are not so marked as might be expected. It was probably Hunter who first distinctly recognised the fact that arsenic, even when introduced outwardly by application to an abraded surface, exerts a specific effect on the mucous membrane of the stomach. Brodie722 states, “Mr. Home informed me that in an experiment made by Mr. Hunter himself, in which arsenic was applied to a wound in a dog, the animal died in twenty-four hours, and the stomach was found to be considerably inflamed. I repeated this experiment several times, taking the precaution of always applying a bandage to prevent the animal licking the wound. The result was that the inflammation of the stomach was commonly more violent and more immediate than when the poison was administered internally, and that it preceded in appearance the inflammation of the wound.”
§ 724. Cases of Poisoning by the External Application of Arsenic.—A mass-poisoning by the external use of arsenical violet powder to infants occurred in England some years ago. Two deaths from this cause were established by coroners’ inquests.723 Dr. Tidy found the violet powders used in the two cases to have the following composition:—
| 1. Per cent. | 2. Per cent. | |
|---|---|---|
| Arsenious Acid, | 38·5 | 38·3 |
| Starch (Potato), | 54·8 | 55·4 |
| Magnesia, &c. | 6·7 | 6·3724 |
| First Quality, sold at 7s. per gross. | |||
| Starch Powder, | 28 | lbs. | |
| Magnesia, | 1 | 1⁄2 | lb. |
| Orris-root, | 1 | lb. | |
| Violet Perfume, | 1 | oz. | |
| Essence of Roses, | 5 | drops. | |
| Second Quality, sold at 6s. per gross. | |||
| Terra Alba (Sulphate of Lime), | 14 | lbs. | |
| Potato Starch, | 21 | lbs. | |
| Magnesia, | 3 | lbs. | |
| Orris-root, | 1 | 1⁄2 | lb. |
| Violet Perfume, | 1 | 1⁄2 | oz. |
| Essence of Roses, | 5 | drops. | |
Although the children were poisoned by absorption through the skin (unless it is allowed that some may have found its way in the form of arsenical dust into the throat, or, what is still more probable, that the infants may from time to time have seized the puff-ball and sucked it), the large quantity of ·421 grm. (6·5 grains) of arsenious acid was separated in the one case, and ·194 grm. (3 grains) in the other. In these cases arose the question which is sure to recur in legal inquiries into poisoning by absorption, viz., whether the poison lying on the surface and folds of the skin could not have been mixed during the post-mortem examination with the organs of the body? In these particular cases special care appears to have been taken, and the answer was satisfactory. It is not amiss, however, to call attention to the extreme precaution which such instances necessitate.
A woman, aged 51, had used a solution of arsenious acid to cure the itch; erysipelas of the body, however, followed, and she died after a long illness—one of the symptoms noted being trembling and paresis of the limbs.725 In a case recorded by Desgranges,726 a young chambermaid had applied to the unwounded scalp an arsenical ointment for the purpose of destroying vermin. She also suffered from a severe erysipelas, and the hair fell off. Quacks have frequently applied various arsenical pastes to ulcers and cancerous breasts with a fatal result. Instances of this abound; in one, a charlatan applied to a chronic ulcer of the leg an arsenical caustic; the patient showed symptoms of violent poisoning, and died on the sixth day.727 In another, a lady suffering from some form of tumour of the breast, applied to an unqualified practitioner, who made from fifteen to twenty punctures with a lancet in the swelling, covered a piece of bread with an arsenical compound, and applied the bread thus prepared to the breast. Twelve hours afterwards symptoms of violent gastric irritation commenced; and vomiting and a sanguinolent diarrhœa followed, with death on the fifth day. Arsenic was found in all the organs.728 Such examples might be multiplied. Arsenic has been in more than one case introduced criminally into the vagina with a fatal result.729 Foderé, e.g., has recorded the case of a maid-servant who poisoned her mistress by intentionally administering several arsenical enemata.730 Arsenious acid again has been respired in the form of vapour. One of the best instances of this is recorded by Taylor, and was the subject of a trial at the York Lent Assizes, 1864. The prisoner placed some burning pyrites at the doorway of a small room, in which there were eight children, including an infant in the cradle. The other children were removed speedily, but the infant was exposed to the vapour for an hour; it suffered from vomiting and diarrhœa, and died in twenty-four hours. There was slight inflammation of the stomach and intestines, the brain and lungs were congested, and the lining membrane of the trachea of a bright red colour. Arsenic was detected in the stomach, in the lungs, and spleen. The pyrites contained arsenic, and the fatal fumes were in effect composed of sulphurous and arsenious acids.
§ 725. Arsenic in Wall-Papers.—It is now an accepted fact that arsenical colours on wall-papers cause illness. The symptoms are those of chronic poisoning, and present nothing distinctive from the effects produced from small doses of arsenic.
Kirschgasser731 has described the symptoms in detail of twenty-six cases. That arsenic is actually present in patients suffering is often susceptible of proof, by examining skilfully and carefully a considerable volume (from one to two days’ collection) of the urine; in most of the cases thus examined arsenic has been discovered. This poisoning is produced, sometimes from the dust, at others from a volatile compound of arsenic, which has the following properties:—It is very volatile (perhaps a gas), it has a strong alliaceous odour, it is not entirely decomposed by a solution of silver nitrate, but is apparently decomposed by a boiling acid solution of potassic permanganate. The author suggests that it may be a compound of CO and As, but this is only a supposition. The existence of this volatile substance has been settled beyond all question by the experiments of Gosio,732 confirmed by those of Charles Robert Sanger.733
This substance appears to be readily enough produced by the action of the common moulds upon organic matter in the presence of small amounts of arsenic; the moulds vary in this property: Mucor, Mucedo, and Aspergillum glaucum react well; on the contrary, Penicillium glaucum, Mucor ramosus, and several others have either no action, or the action is but slight. One mould, the Penicillium brevicaule, has quite a special endowment in forming this peculiar arsenical compound; so much so, that Gosio has proposed its use as a reagent for arsenic, the garlic odour being perceived when the fungus is made to grow in solutions containing organic matter and only traces of arsenic.
§ 726. Forms of Arsenical Poisoning.—There are at least four distinct forms of arsenical poisoning, viz., an acute, subacute, a nervous, and a chronic form.
Acute Form.—All those cases in which the inflammatory symptoms are severe from the commencement, and in which the sufferer dies within twenty-four hours, may be called acute. The commencement of the symptoms in these cases is always within the hour; they have been known, indeed, to occur within eight minutes, but the most usual time is from twenty minutes to half an hour. There is an acrid feeling in the throat, with nausea; vomiting soon sets in, the ejected matters being at first composed of the substances eaten; later they may be bilious or even bloody, or composed of a whitish liquid. Diarrhœa follows and accompanies the vomiting, the motions are sometimes like those met with in ordinary diarrhœa and English cholera, and sometimes bloody. There is coldness of the extremities, with great feebleness, and the pulse is small and difficult to feel. The face, at first very pale, takes a bluish tint, the temperature falls still lower; the patient sinks in collapse, and death takes place in from five to twenty hours after the taking of the poison.
There can scarcely be said to be any clinical feature which distinguishes the above description from that of cholera; and supposing that cholera were epidemic, and no suspicious circumstance apparently present, there can be little doubt that a most experienced physician might mistake the cause of the malady, unless surrounding circumstances give some hint or clue to it. In the acute form diarrhœa may be absent, and the patient die, as it were, from “shock.” This was probably the cause of death in a case related by Casper,734 that of Julius Bolle, poisoned by his wife. He took an unknown quantity of arsenic in solution at seven in the morning, and in about three-quarters of an hour afterwards suffered from pain and vomiting, and died in little more than three hours. There were no signs of inflammation in the stomach and intestines, but from the contents of the stomach were separated ·0132 grm. of arsenious acid, and ·00513 grm. from pieces of the liver, spleen, kidneys, lung, and blood. The dose actually taken is supposed not to have been less than ·388 grm. (6 grains).
§ 727. The Subacute Form.—The subacute form is that which is most common; it exhibits some variety of phenomena, and individual cases vary much in the matter of time. The commencement of symptoms is, as in the most acute form, usually within the hour, but exceptions to this rule occur. In a case quoted by Taylor,735 and recorded by M. Tonnelier, the poison did not cause any marked illness for eight hours; it was found, on post-mortem examination, that a cyst had been formed in the stomach which sheathed the arsenic over, and in some degree explained this delay. In another case, again, ten hours elapsed, and this is considered to be the maximum period yet observed. As with the acute form, there is a feeling of nausea, followed by vomiting, which continues although the stomach is quite empty; at first the ejected matter is a watery fluid, but later it may be streaked with blood. The tongue is thickly coated; there is great thirst, but the drinking of any liquid (even of ice-cold water) increases the vomiting. Nearly always pain is felt in the epigastrium, spreading all over the abdomen, and extending to the loin (which is tense and tender on pressure). Deglutition is often painful, and is accompanied by a sort of spasmodic constriction of the pharyngeal muscles. Diarrhœa follows the vomiting, and has the same characters as that previously described; occasionally, however, this feature is absent. In the case recorded by Martineau,736 a man, aged 25, was seized at 10 A.M. suddenly with vomiting, which persisted all that day and the next, during which time the bowels were obstinately confined. On the second day a purgative was administered, whereupon diarrhœa set in, and continued until his death, which occurred in about two days and sixteen hours from the commencement of the symptoms. This case is also remarkable from the absence of pain or tenderness of the abdomen.
In subacute cases the urine has several times been suppressed, and it is generally scanty and red in colour. Irregularity of the heart’s action and feebleness are tolerably constant phenomena. As the end approaches, there is excessive muscular weakness, the face is pale, the eyes hollow; the mucous membranes first, and then the skin, take a bluish tint; the skin itself is covered with perspiration, and there has been noticed a peculiar odour, which has been likened to arsine (arseniuretted hydrogen). The respiration is troubled, convulsive movements of the limbs have been observed, and cramps in the calves of the legs; death follows in a variable time—from twenty-four hours to several days. In certain cases there is a curious remission after violent symptoms, the patient rallies and seems to have recovered; but the appearance is deceptive, for the symptoms recur, and death follows. Recovery may also take place partially from the primary effects, and then inflammatory changes in the stomach, &c., set in, with fever and the ordinary symptoms which are common in all internal inflammation.
A single dose of arsenious acid may cause a prolonged and fatal illness, one of the best known examples being that of the suicide of the Duc de Praslin,737 who took, with suicidal intent, on Wednesday, August 18, 1847, a dose of arsenious acid. The exact time of the act could not be ascertained, but the first effects appeared at 10 P.M.; there were the usual signs of vomiting, followed on the next day by diarrhœa, fainting, and extreme feebleness of the pulse. On Friday there was a remission of the symptoms, but great coldness of the limbs, intermittency and feebleness of the heart’s action, and depression. On Saturday there was slight fever, but no pain or tenderness in the abdomen, vomiting, or diarrhœa; on this day no urine was passed. On the Sunday he complained of a severe constriction of the throat, and deglutition was extremely painful; thirst was extreme, the tongue intensely red, as well as the mucous membrane of the mouth and pharynx, and the patient had a sensation of burning from the mouth to the anus. The abdomen was painful and distended, the heat of the skin was pronounced, the pulse frequent and irregular,—sometimes strong, at others feeble,—the bowels had to be relieved by injections, the urine was in very small quantity; during the night there was no sleep. The duke died at 4.35 A.M. on Tuesday the 24th, the sixth day; intelligence was retained to the last. As the end approached, the respiration became embarrassed, the body extremely cold, and the pulse very frequent.
§ 728. In the nervous form the ordinary vomiting and purging are either entirely suppressed, or present in but feeble degree; and under this heading are classed the rare cases in which, in place of the ordinary symptoms, affections of the nervous system predominate. Narcotism, paresis, deepening into paralysis, delirium, and even acute mania, as well as epileptiform convulsions, have all been recorded. In short, the symptoms show so much variety, that an idea of the malady produced in this very rare form can only be obtained by studying the clinical history of cases which have presented this aspect. In a case recorded by Guilbert,738 a man, thirty-five years of age, had swallowed a solution of arsenic, half of which was immediately rejected by vomiting. A little while afterwards his respiration became laborious; the eyes were bathed with tears, which were so acrid as to inflame the eyelids and the cheeks; the muscles of the face were from time to time convulsed; he perspired much, and the perspiration had a fœtid odour; there was some diarrhœa, the urine was suppressed, and from time to time he was delirious. Afterwards the convulsions became general, and the symptoms continued with more or less severity for five days. On the sixth a copious miliary eruption broke out, and the symptoms became less severe. The eruption during fifteen days every now and again reappeared, and at the end of that time the patient was convalescent, but weak, liable to ophthalmia, and had a universal trembling of the limbs.
In one of Brodie’s739 experiments on rabbits, 7 grains of arsenious acid were inserted in a wound in the back; the effect of which was to paralyse the hind legs. In other experiments on animals, paralysis of the hind legs has been frequently noticed, but paralysis certainly is rare in man; in the case, however, recorded by Barrier,740 of the five men who took by mistake a solution of arsenious acid, one of them was found stretched on the ground with the inferior extremities paralysed.
In a case of “mass” poisoning reported by Dr. Coqueret,741 three persons ate by mistake an unknown quantity of arsenious acid—two of them only suffered slightly, but the third severely, vomiting occurring almost immediately, and continuing with frequency until the end of the fourth day. Two hours after swallowing the poison, the patient took the hydrated oxide of iron as an antidote. On the sixth day there was stupor and a semi-delirious state, with an eruption of a pustular character compared to that of the small-pox. These symptoms continued more or less until the fifteenth day, when they diminished, and ultimately the patient recovered. In a case related by Tardieu,742 in which a person died on the eleventh day from the effects of the poison, towards the end, as a specially marked symptom, there was noted hyperæsthesia of the inferior extremities, so that the least touch was painful.
§ 729. Absence of Symptoms.—In a few cases there have been a remarkable absence of symptoms, and this both in man and animals. Seven horses were fed with oats accidentally mixed with arseniate of soda. The first succumbed three hours after taking the poison, without having presented any symptom whatever; he fell suddenly, and in a short time expired.743 It is related by Orfila,744 that a woman, aged 27, expired in about twelve hours from a large dose of arsenious acid; there were the usual post-mortem appearances, but in life no sign of pain, no vomiting, and but little thirst.
§ 730. Slow Poisoning.—Slow poisoning has been caused accidentally by arsenical wall-paper, in the manufacture of arsenical pigments, by the admixture of small quantities of arsenic with salt or other condiments, and repeated small doses have been used for criminally producing a fatal illness intended to simulate disease from natural causes. The illness produced by small intermittent doses may closely resemble in miniature, as it were, those produced by large amounts; but, on the other hand, they may be different and scarcely to be described otherwise than as a general condition of ill-health and malaise. In such cases there is loss of appetite, feebleness, and not unfrequently a slight yellowness of the skin. A fairly constant effect seen, when a solution of arsenious acid is given continuously for a long time, is an inflammation of the conjunctivæ, as well as of the nasal mucous membrane—the patient complains of “always having a cold.” This inflammatory action also affects the pharynx, and may extend to the air-passages, and even to the lung-tissue. At the same time there is often seen an exanthem, which has received a specific name—“eczema arsenicale.” Salivation is present, the gums are sore, at times lacerated. In chronic poisoning by arsenic, nervous symptoms are almost constant, and exhibit great variety; there may be numbness, or the opposite condition, hyperæsthesia, in the extremities. In certain cases fainting, paresis, paralysis, and sometimes convulsions occur; towards the end a sort of hectic fever supervenes, and the patient dies of exhaustion.
§ 731. The Maybrick Case.745—The Maybrick case may be considered an example of poisoning extending over a considerable period of time:—Mr. James Maybrick, a Liverpool cotton-broker, aged 49, married Florence Elizabeth, an American lady, aged 21. They had two children. The marriage proved an unhappy one. Some two years before his death in May 1889 they had occupied two separate rooms. Seven weeks before the husband’s death, Mrs. Maybrick went to London on a false pretext, and lived for some days at an hotel, ostensibly the wife of another man. Two days after her return, Mr. and Mrs. Maybrick attended the Grand National race meeting, and there a serious quarrel arose between them respecting the man with whom she had cohabited in London; they returned from the race, each separately, and she slept apart. Next day an apparent reconciliation took place through the intervention of Dr. Fuller, the family medical attendant.
On or about April 12-19th, 1889, Mrs. Maybrick purchased arsenical fly-papers. On April 13-20th Mr. Maybrick visited London, and consulted Dr. Fuller for dyspepsia, who prescribed nux vomica, acids, and mild remedies (but no arsenic); in one bottle of medicine, ostensibly made according to Dr. Fuller’s prescription, arsenic was subsequently found.
Up to Saturday, April 27th, Mr. Maybrick was in his usual health; he was then sick, numbed, and in pain, and had cramps; he told his clerk he had been an hour in the water-closet, but whether for diarrhœa or constipation does not appear; he ascribed the symptoms to an overdose of Fuller’s medicine. About this date fly-papers were found by the servants soaking in Mrs. Maybrick’s bedroom in a sponge-basin, carefully covered up. On the 29th she again purchased two dozen fly-papers from another chemist. On April 28th Mr. Maybrick was sick and ill; at 11 A.M. Dr. R. Humphreys was called in; Mr. Maybrick complained of a peculiar sensation about his heart, and said he was in dread of paralysis. He attributed his illness to a strong cup of tea taken before breakfast. On the following day he was better, and on the 30th still improving. On May 1st and 2nd Mr. Maybrick went to his office and lunched, both days, off revalenta food, prepared at home and warmed at his office in a new saucepan purchased for the occasion; on one of these days the lunch was forgotten, and was sent to Mr. Maybrick by his wife; and on one of the two days, it is not clear which, Mr. Maybrick complained that his lunch did not agree with him, and he attributed it to inferior sherry put into his food.
In a jug found at the office, and in which food had been taken there, a trace of the food still remained after Mr. Maybrick’s death, and arsenic was found therein.
On May 3rd the last fatal illness set in. It is uncertain what food he had after breakfast; he went to the office, and returned home between 5 and 6 P.M. He had been seen by Dr. Humphreys in the morning, and appeared then not quite so well; he found him at midnight suffering from what he thought was severe sciatica; the patient said he had been sick from revalenta. On May 4th he was continually sick, nothing could be retained on the stomach, but the sciatic pain was gone; on May 5th the vomiting continued, the patient complained of the sensation of a hair sticking in the throat, and of a filthy taste in the mouth. The throat and fauces were only slightly reddened, the tongue was furred.
On May 6th there was less vomiting, but otherwise the condition was the same, and Fowler’s solution ordered, but only a quantity equal to 1⁄300 grain was actually taken.
May 7th the condition was improved, but there was no increase of power. Dr. W. Carter was called in consultation. The vomiting was passing away, and diarrhœa commencing. The throat was red, dry, and glazed; there were incessant attempts to cough up an imaginary hair. No cramps, no pain in the stomach or intestines, nor conjunctivitis. On this day the first direct evidence of diarrhœa is recorded, the medical men actually seeing a loose motion. The result of the consultation was that Mr. Maybrick must have taken some irritant in his food or drink.
On the 8th a professional nurse took charge. During the 8th and 9th severe tenesmus set in with diarrhœa, and blood was observed in the fæces. Now arsenic was suspected, the urine was examined by Dr. Humphreys, and a rough analysis was made of some Neaves’ food which the patient had been taking.
The patient died on the 10th, at 8.30 P.M.
The post-mortem appearances were as follows:—
The tongue was dark, the top of the gullet slightly red, but otherwise healthy, save at the lower end, where the mucous membrane was gelatinous, and was dotted over with black dots, like frogs’ spawn.
There was a small shallow ulcer in the mucous membrane of the larynx at the back of the epiglottis. The free margin of the epiglottis was rough and eroded; and on the posterior aspect of the ericoid cartilage there were two small red patches. In the stomach were from 5-6 ozs. of brownish fluid. At the cardiac end there was a large vermilion-red patch, interspersed here and there with small dark ecchymoses (spoken of by Dr. Humphreys as a flea-bitten appearance); to this followed a non-inflamed space, and near the pyloric orifice, and extending 2 inches from it, was another red inflamed portion of mucous membrane. In the small intestine the mucous membrane was red and inflamed, from 3 inches below the pylorus to about 3 feet downwards. About 18 or 20 feet lower down, i.e., a little below the ileo-cæcal valve, the mucous membrane was again inflamed to a lesser extent over a space of about 2 feet; the lower end of the rectum was also red and inflamed. No arsenic was found in the stomach or its contents, or in the spleen. Arsenic was present in the liver, in the intestines, and in the kidneys. The quantity separated altogether amounted to over 0·1 grain. The liver weighed 48 ozs., and from 12 ozs. of the liver 0·076 grain of arsenic, reckoned as As2O3, was separated.
The whole course of the symptoms and the post-mortem examination showed that the deceased died from an irritant poison; and from the fact of a small quantity of arsenic having been found in the body, there can be little doubt but that the poison was arsenic. The symptoms were somewhat anomalous, but not more so than in other recorded cases of undoubted arsenical poisoning. The facts that tended to connect the accused with the death were as follows:—On the night of either May 9th or the 10th Mrs. Maybrick was observed to remove from the table an opened bottle of Valentine’s meat juice, and take it into an inner dressing-room, and then replace it—the acts being surreptitious. In replacing it, she was observed to take it either from the pocket of her dressing-gown or from an inner pocket. The lining of this pocket was found to be impregnated with As2O3. The juice was found to contain 0·5 grain As2O3, and the liquid was of lower gravity than commercial juice; it had probably, therefore, been diluted.
The following is a list of things containing arsenic:—
Mrs. Maybrick’s dressing-gown.
Mrs. Ma„brick’s apron.
A handkerchief wrapped around a bottle.
Packet of arsenic “for cats.” (Arsenious acid mixed with charcoal.) Tumbler containing milk, with handkerchief soaking in it; at least 20 grains of As2O3 in the tumbler mixed with charcoal.
A portion of a handkerchief.
A bottle containing a strong solution of arsenious acid and several grains of undissolved arsenious acid.
A bottle containing from 15-20 grains of solid arsenic and a few drops of solution.
A saturated solution of arsenious acid and some solid arsenious acid.
Valentine’s meat juice.
Price’s glycerin; 2⁄3 grain in the whole bottle.
A bottle containing 0·1 grain of arsenious acid.
A bottle from Mr. Maybrick’s office containing a few drops of medicine prescribed by Dr. Fuller (decidedly arsenical).
Jug from the office with remains of food.
Sediment from trap of w.c. and lavatory drain containing As2O3.
Mrs. Maybrick was convicted, but afterwards the sentence was commuted to penal servitude for life.
§ 732. Post-mortem Appearances in Animals.—P. Hugo746 has made some minute researches as to the pathological appearances met with in animals. His experiments were made on seven dogs, eight guinea-pigs, five rabbits, two pigeons, and five cats—all poisoned by arsenious acid. According to Hugo, so far as these animals were concerned, changes were more constant in the intestine than in the stomach.
Stomach.—Changes in the mucous membrane were especially noticed in the great curvature and towards the pylorus; the pylorus itself, and a part of the cardiac portion, remained unchanged. The mucous membrane in dogs and cats was red, with a tinge of blue—in many cases the redness was in streaks, with injection of the capillaries. The stomach of plant-eaters was less altered, and a microscopical examination of the mucous tissues did not show any fatty change.
The Intestines.—In dogs and cats changes were evident; in rabbits and guinea-pigs they were not so marked, but the intestines of the last were extremely tender and brittle, very moist, and filled with a slimy, serous, grey-white fluid; nevertheless, the changes in all these animals appear to be of essentially the same nature. The most striking effect is the shedding of a pseudo-membrane; in quite recent cases there is a layer of from 1 to 11⁄2 mm. wide of a transparent, frog-spawn-like jelly streaking the intestine. In later stages it becomes thicker, while occasionally it resembles a diphtheritic exudation. The mucous membrane itself is deep purple-red, showing up by the side of the pseudo-membrane. With regard to the villi, the epithelial layer is detached, and the capillary network filled with blood and enlarged.
The Liver.—Hugo met only occasionally with fatty degeneration of the liver, but there was marked steatosis of the epithelium of the gall-bladder of dogs. A fact not prominently noticed before, is (at all events, in dogs) a serous transudation into the pleural sac and acute œdema of the lungs; the exudation may be excessive, so that more than 100 c.c. of serous fluid can be obtained from the thorax; there is also usually much fluid in the pericardium. In two of Hugo’s experiments there was fluid in the cerebral ventricles; and in all there was increased moisture of the brain substance with injection of the capillary vessels, especially of the pia.
§ 733. Post-mortem Appearances.—A remarkable preservation of the body is commonly, but not constantly, observed. When it does occur it may have great significance, particularly when the body is placed under conditions in which it might be expected to decompose rapidly. In the celebrated Continental case of the apothecary Speichert (1876), Speichert’s wife was exhumed eleven months after death. The coffin stood partly in water, the corpse was mummified. The organs contained arsenic, the churchyard earth no arsenic. R. Koch was unable to explain the preservation of the body, under these conditions, in no other way than from the effect of arsenic; and this circumstance, with others, was an important element which led to the conviction of Speichert.
When arsenious acid is swallowed in substance or solution, the most marked change is that in the mucous membrane of the stomach and intestines; and, even when the poison has been absorbed by the skin, or taken in any other way, there may be a very pronounced inflammatory action. On the other hand, this is occasionally absent. Orfila747 relates a case in which a man died in thirteen hours after having taken 12 grms. of arsenious acid:—“The mucous membrane of the stomach presented in its whole extent no trace of inflammation, no redness, and no alteration of texture.” Many other similar cases are on record; and, according to Harvey’s statistics, in 197 cases, 36 (about 18·2 per cent.) presented no lesion of the stomach.
The usual changes produced by arsenious acid may be studied in the museums of the London hospitals. In Guy’s Hospital Museum there are three preparations. In preparation 179832 is seen a large stomach with the mucous membrane at certain points abraded, and at the great curvature the whole coats are thinned; it is also somewhat congested. In preparation 179864 is a portion of coagulated lymph, from the stomach of a lad, aged 14, who had taken accidentally a piece of cheese charged with arsenious acid, prepared for the purpose of destroying rats. He lived twenty-eight hours, and presented the ordinary symptoms. The lymph has a membranous appearance, and the rugæ of the stomach are impressed upon it. It is said when recent to have presented numerous bright bloody spots, although there was no visible breach of substance on the surface of the stomach. The mucous membrane of the stomach is stated to have been injected, and there was also diffuse injection of the duodenum. Preparation 179880 is the stomach of a person who survived thirteen hours after taking a fatal dose of arsenious acid; and in the same museum there is a wax model of the appearances which the fresh preparation exhibited, showing a large oval patch coated with mucus and the poison. The stomach was intensely inflamed, the cæcum injected. The rest of the intestine was healthy.
In the museum of University College there are two preparations, one748 exhibiting intense swelling and congestion of the gastric mucous membrane, which is of a perfectly vermilion colour. Another preparation (No. 2868) shows the effect of a small dose of arsenic on the stomach; there are spots of arborescent extravasation, and slight congestion of the summits of the rugæ, but in other respects it is normal. There is also a cast of Peyer’s patches from the same case, showing great prominence of the glands, with some injection of the intestinal mucous membrane.
In St. Thomas’ Hospital there is an interesting preparation (No. 8) showing the gastric mucous membrane dotted all over with minute ulcers, none of which have an inflammatory zone.749 I have not, however, seen in any museum a preparation of the curious emphysematous condition of the mucous membrane, which has more than once been met with. For example, in a case related by Tardieu,750 Schwann, a labourer, died from the effects of arsenic in thirty-six hours. The autopsy showed that the mucous membrane of the stomach and small intestine was covered with a pasty coating, and was elevated in nearly its whole extent by bullæ filled with gas, forming true emphysematous swellings which encroached upon the diameter of the intestine. There was neither redness nor ulceration, but the mucous membrane was softened.
The author saw, many years ago, at Barnard Castle, an autopsy made on a gentleman who died from arsenic. In this case the mucous membrane of the stomach presented a peculiar appearance, being raised here and there by little blebs, and very slightly reddened.
§ 734. The inflammatory and other changes rarely affect the gullet. Brodie751 never observed inflammation of the œsophagus as an effect of arsenic; but, when arsenic is swallowed in the solid state, as in the suicide of Soufflard, graphically described by Orfila,752 it may be affected. In Soufflard’s case there was a vivid injection of the pharynx and gullet.
In many instances, when the arsenic has been taken in the solid form, the crystals with mucus and other matters adhere to the lining membrane. I have seen in the stomach of a horse, poisoned by an ounce of arsenic, an exquisite example of this. The inflammatory changes may be recognised many months after death owing to the antiseptic properties of arsenic; nevertheless, great caution is necessary in giving an opinion, for there is often a remarkable redness induced by putrefactive changes in healthy stomachs. Casper,753 on this point, very justly observes:—“If Orfila quotes a case from Lepelletier, in which the inflammatory redness of the mucous membrane of the stomach was to be recognised after nine months’ interment, and if Taylor cites two cases in which it was observed nineteen and twenty-one months after death respectively, this is in contradiction of all that I, on my part, have seen in the very numerous exhumed corpses examined by me in relation to the gradual progress of putrefaction and of saponification, and I cannot help here suspecting a confusion with the putrefactive imbibition redness of the mucous membrane.”
If examined microscopically, the liver and kidneys show no change, save a fatty degeneration and infiltration of the epithelial cells. In the muscular substance of the heart, under the endocardium, there is almost constantly noticed ecchymosis. In the most acute cases, in which a cholera-like diarrhœa has exhausted the sufferer, the blood may be thickened from loss of its aqueous constituents, and the whole of the organs will present that singularly dry appearance found in all cases in which there has been a copious draining away of the body fluids. In the narcotic form of arsenical poisoning, the vessels of the brain have been noted as congested, but this congestion is neither marked nor pathognomonic. Among the rare pathological changes may be classed glossitis, in which the whole tongue has swollen, and is found so large as almost to fill the mouth. This has been explained, in one case, as caused by solid arsenious acid having been left a little time in the mouth before swallowing it. On the other hand, it has also been observed when the poison has been absorbed from a cutaneous application. When arsenic has been introduced into the vagina, the ordinary traces of inflammatory action have been seen, and, even without direct contact, an inflammation of the male and female sexual organs has been recorded, extending so far as gangrene. As a rule, putrefaction is remarkably retarded, and is especially slow in those organs which contain arsenic; so that, if the poison has been swallowed, the stomach will retain its form, and, even to a certain extent, its natural appearance, for an indefinite period. In corpses long buried of persons dying from arsenical poisoning, the ordinary process of decay gives place to a saponification, and such bodies present a striking contrast to others buried in the same graveyard. This retardation of putrefaction is what might, à priori, be expected, for arsenic has been long in use as a preservative of organic tissues.
§ 735. Physiological Action of Arsenic.—The older view with regard to the essential action of arsenic was, without doubt, that the effects were mainly local, and that death ensued from the corrosive action on the stomach and other tissues—a view which is in its entirety no longer accepted; nevertheless, it is perfectly true that arsenic has a corrosive local action; it will raise blisters on the skin, will inflame the tongue or mucous membranes with which it comes in contact; and, in those rapid cases in which extensive lesions have been found in the alimentary canal, it can hardly be denied that instances of death have occurred more from the local than the constitutional action. In the vast majority of cases, however, there is certainly insufficient local action to account for death, and we must refer the lethal result to a more profound and intimate effect on the nervous centres. The curious fact, that, when arsenic is absorbed from a cutaneous surface or from a wound, the mucous membrane of the stomach inflames, is explained by the absorption of the arsenic into the blood and its separation by the mucous membrane, in its passage exerting an irritant action. The diarrhœa and hyperæmia of the internal abdominal organs have been referred to a paralysis of the splanchnic nerves, but Esser considers them due to an irritation of the ganglia in the intestinal walls. Binz has advanced a new and original theory as to the action of arsenious acid; he considers that the protoplasm of the cells of many tissues possess the power of oxidising arsenious acid to arsenic acid, and this arsenic acid is again, by the same agency, reduced to arsenious acid, in this way, by the alternate oxidation and reduction of the arsenious acid, the cells are decomposed, and a fatty degeneration takes place. Thus arsenic causes fatty changes in the liver, kidney, and other cells by a process analogous to the action of phosphorus. T. Araki754 also considers that both arsenic and phosphorus lessen oxidation, and points out that lactic acid appears in the urine when either of these poisons are taken, such acid being the result of insufficient oxidation. A notable diminution of arterial pressure has been observed. In an experiment by Hugo755 ·03 grm. of As2O3 was injected intravenously, the normal arterial pressure being 178 mm. Ten minutes after injection the pressure sank to 47 mm.; in sixteen minutes it again rose to 127 mm. Accumulative action of arsenic does not occur. Hebra has given, in skin diseases, during many months, a total quantity of 12 grms. without evil result.
§ 736. Elimination of Arsenic.—Arsenic is separated especially by the urine,756 then through the bile, and by the perspiration. The eruption often observed on the skin has been referred to the local action of small quantities of arsenic in this way eliminated. It is found in the urine first after from five to six hours, but the elimination from a single dose is not finished till a period of from five to eight days; it has often been looked for twelve days after taking it, but very seldom found. According to Vitali, the arsenic in the urine is not free, but probably displaces phosphorus in phospho-glyceric acid; possibly it may also replace phosphorus in lecithin.
§ 737. Antidote and Treatment.—In any case in which there is opportunity for immediate treatment, ferric hydrate should be administered as an antidote. Ferric hydrate converts the soluble arsenious acid into the insoluble ferric arseniate, the ferric oxide being reduced to ferrous oxide. It is necessary to use ferric hydrate recently prepared, for if dried it changes into an oxyhydrate, or even if kept under water the same change occurs, so that (according to the experiments of Messrs. T. & H. Smith) after four months the power of the moist mass is reduced to one-half, and after five months to one-fourth.
It is obvious that ferric hydrate is not in the true sense of the word an antidote, for it will only act when it comes in contact with the arsenious acid; and, when once the poison has been removed from the stomach by absorption into the tissues, the administration of the hydrate is absolutely useless. Ferric hydrate may be readily prepared by adding strong ammonia to the solution or tincture of ferric chloride, found in every medical man’s surgery and in every chemist’s shop, care being taken to add no caustic excess of ammonia; the liquid need not be filtered, but should be at once administered. With regard to other methods of medical treatment, they are simply those suggested by the symptoms and well-known effects of the poison. When absorbed, the drinking of water in excess cannot but assist its elimination by the kidneys.
§ 738. Detection of Arsenic.—The analyst may have to identify arsenic in substance, in solution, in alloys, in wall-papers, in earth, and in various animal, fatty, resinous, or other organic matters.
Arsenious Acid in Substance.—The general characters of arsenious acid have been already described, and are themselves so marked as to be unmistakable. The following are the most conclusive tests:—
(1) A small fragment placed in the subliming cell (p. 258), and heated to about the temperature of 137·7° (286° F.), at once sublimes in the form of an amorphous powder, if the upper glass disc is cool; but if heated (as it should be) to nearly the same temperature as the lower, characteristic crystals are obtained, remarkable for their brilliancy and permanency, and almost always distinct and separate. The prevailing form is the regular octahedron, but the rhombic dodecahedron, the rectangular prism, superimposed crystals, half crystals, deep triangular plates like tetrahedra, and irregular and confused forms, all occasionally occur.
(2) A beautiful and well-known test is that of Berzelius:—A small hard-glass tube is taken, and the closed end drawn out to the size of a knitting needle. Within the extreme point of this fine part is placed the fragment (which may be no more than a milligramme) and a splinter of charcoal, fine enough to enter freely the narrow part, as shown in the figure. The portion of the tube containing the charcoal (e) is first heated until it glows, and then the extreme end; if arsenic is present, a mirror-like coating is easily obtained in the broader portion of the tube (d). That this coating is really arsenical can be established by the behaviour of metallic crusts of arsenic towards solvents (as given at p. 557). The portion of the tube containing the crust may also be broken up, put in a very short, wide test-tube (the mouth of which is occupied by a circle of thin microscopic glass) and heated, when the arsenic will sublime on to the glass disc, partly as a metal and partly as crystalline arsenious acid.
(3) Arsenious acid, itself inodorous, when heated on coal, after mixing it with moist oxalate of potash, evolves a peculiar garlic-like odour. To this test oxide of antimony adulterated with arsenic will respond, if there is only a thousandth part present. Simply projecting arsenious acid on either red-hot charcoal or iron produces the same odour.
(4) A little bit of arsenious acid, heated in a matrass with two or three times its weight of acetate of potash, evolves the unsupportable odour of kakodyl.
Arsenites and Arseniates, mixed with oxalate of soda and heated in a matrass, afford distinct mirrors, especially the arsenites of the earths and silver; those of copper and iron are rather less distinct.
Sulphides of Arsenic are reduced by any of the processes described on p. 573 et seq.
In Solution.—An acid solution of arsenious acid gives, when treated with SH2, a canary-yellow precipitate, soluble in ammonia, carbonate of ammonia, and bisulphite of potash, and also a metallic sublimate when heated in a tube with the reducing agents in the manner described at p. 575. By these properties the sulphide is distinguished and, indeed, separated from antimony, tin, and cadmium.
The sulphides of tin and cadmium are certainly also yellow, but the latter is quite insoluble in ammonia, while the former gives no metallic sublimate when heated with reducing substances.
The sulphide of antimony, again, is orange, and quite insoluble in potassic bisulphite, and scarcely dissolves in ammonia.
A small piece of sodium amalgam placed in a test-tube or flask containing an arsenic-holding liquid, or the liquid made alkaline with soda or potash and a little bit of aluminium added, produces in a short time arsine, which will blacken a piece of paper, soaked in nitrate of silver, and inserted in the mouth of the flask. This is certainly the most convenient test for arsenic. No antimoniuretted hydrogen (stibine) is given off from an alkaline solution and no SH2.
Marsh’s Original Test for Arsenic consisted in evolving nascent hydrogen by zinc and sulphuric acid, and then adding the liquid to be tested. The apparatus for Marsh’s test, in its simplest form, consists of a flask provided with a cork conveying two tubes, one a funnel reaching nearly to the bottom of the flask; the other, a delivery tube, which is of some length, is provided with a chloride of calcium bulb,757 and towards the end is turned up at right angles, the end being narrowed. By evolving hydrogen from zinc and sulphuric acid, and then adding portions of the liquid through the funnel, arseniuretted hydrogen in a dry state is driven along the leading tube, can be ignited on its issue, and on depressing a piece of cold porcelain, a dark metallic spot of arsenic is obtained.758 Or, if any portion of the tube be made red-hot, the metal is deposited in the same way as a ring. The apparatus admits of much complication and variety. One of the most useful additions is, perhaps, the interposition of a small gasometer. This consists of a cylindrical glass vessel with entrance and exit tubes, open at the bottom, immersed in water in a larger vessel, and counterpoised by weights and rollers, exactly like the large gasometers used at gasworks; the exit tube must have a stop-cock, and the gas must pass over calcic chloride in order to dry it thoroughly.
M. Blondlot has observed759 that if pure zinc, a weak solution of arsenious acid, and a sulphuric acid containing nitric acid or nitrous compounds, be mixed together, the arsenic passes into a solid hydrate, which is deposited on the surface of the zinc; this is, however, prevented by the addition of a little stannous chloride dissolved in hydrochloric acid.
The precautions to be observed in Marsh’s test are:—
(1) Absolute freedom of the reagents used from arsenic, antimony,760 and other impurities.
(2) The sulphuric acid should be diluted with five times its weight of water, and if freshly prepared should be cooled before use. Strong acid must not be employed.761
(3) The fluid to be tested should be poured in little by little.
(4) Nitrous compounds, nitric acid, hydrochloric acid, chlorides, are all more or less prejudicial.
(5) The gas should come off regularly in not too strong a stream, nor out of too small an opening.
(6) The gas should pass through the red-hot tube at least one hour, if no stain is at once detected.
(7) Towards the end of the operation, a solution of stannous chloride in hydrochloric acid is to be added to the contents of the flask. This addition precipitates any arsenic present in a finely divided state, in which it is readily attacked by nascent hydrogen.762
The characteristics of the metallic stains which may occur either on glass or porcelain in the use of Marsh’s test, may be noted as under:—
| Mirror or Crust of Arsenic | Mirror or Crust of Antimony |
|---|---|
| Is deposited at a little distance from the flame. | Is deposited close to the flame, and on both sides of it, and is therefore notched. |
| An arsenical stain is in two portions, the one brownish, the other a glittering black. | The stain is tolerably homogeneous, and usually has a tin-like lustre. |
| On heating, it is rapidly volatilised as arsenious acid. | Volatilisation very slow; no crystalline sublimate obtainable. |
| On transmission of a stream of SH2, whilst immediately behind the stain a gentle heat is applied, the arsenic is changed to yellow sulphide;763 if dry ClH is now transmitted, the arsenical sulphide is unchanged. | The same process applied in the case of antimony produces the orange or black sulphide; and on passing dry ClH, chloride of antimony volatilises without the application of heat. |
| Chloride of lime dissolves the arsenic completely. | Antimony not affected. |
| Protochloride of tin has no action on metallic arsenic. | Dissolves slowly but completely the antimony stain. |
| The arsenic stain, dissolved in aqua regia, or ClH and chlorate of potash, and then treated with tartaric acid, ammonia, and magnesia mixture, gives a precipitate of ammonia magnesian arseniate.764 | No precipitate with antimony. |
The mirror or crust of arsenic is usually described and weighed as being composed of the pure metal, but J. W. Rettgers has investigated the matter, and the following is an abstract of his results:—
There is no amorphous form of arsenic, the variety generally thus called being crystalline. Two modifications can be distinguished: the one being a hexagonal silver-white variety possessed of metallic lustre, specifically heavier and less volatile than the second kind, which is black in colour, crystallises apparently in the regular system, and constitutes the true arsenic mirror. The former modification corresponds to red hexagonal phosphorus (red phosphorus having been recently proved by the author to be crystalline), and the latter to yellow phosphorus, which crystallises in the regular system. Both modifications of arsenic are perfectly opaque; deposits which are yellow or brown, and more or less transparent, consist of the suboxide and hydride, As2O and AsH. The brown spot on porcelain produced by contact with a flame of arseniuretted hydrogen is not a thin film of As, but one of the brown solid hydride AsH, formed by the decomposition of AsH3. This view is confirmed by the fact that arsenic sublimed in an indifferent gas (e.g., CO2) is deposited in one or other of the modifications described above, the brown transparent product being obtained only in the presence of H or O. Moreover, pure arsenic is insoluble in all solvents, whereas the film on porcelain (AsH) is soluble in many solvents, including hydrocarbons of the benzene series (e.g., xylene), warm methylene iodide, and hot caustic potash.
Hence quantitative results from weighing arsenical mirrors can never be accurate, because the mirrors consist of mixtures of hydride and suboxide.
Reinsch’s Test.—A piece of bright copper foil, boiled in an acid liquid containing either arsenic or antimony, or both, becomes coated with a dark deposit of antimony or arsenic, as the case may be. The arsenical stain, according to Lippert, is a true alloy, consisting of 1 arsenic to 5 copper.765 Properly applied, the copper will withdraw every trace of arsenic or antimony from a solution. Dr. John Clark766 has lately introduced some improvements in Reinsch’s process. His experiments have been directed to the means of proving the presence of arsenic or antimony in the stain on the copper with greater certainty, and at the same time estimating the amount when they occur together.
The material to be tested is boiled gently in a porcelain vessel with dilute hydrochloric acid and a small strip of copper about 1 inch long by 1⁄4 inch broad, till the absence of arsenic or antimony has been ascertained, or a coating has been produced. When the coating is decided, the piece of copper is taken out, washed first with water, then with a little alcohol to get rid of fatty matter, and finally with water. It is then placed in a mixture of dilute caustic potash and peroxide of hydrogen, and allowed to digest in the cold. At the same time a second piece of copper is introduced into the material which has given a deposit on the first piece, the washings of the first piece being added, and the boiling continued.
The treatment of the first piece of copper by caustic potash and peroxide of hydrogen dissolves any antimony or arsenic and restores the copper to its original brightness; when this is accomplished, the second piece of copper is taken out and replaced by the first, and this second piece, if stained, is digested with potash, peroxide of hydrogen, and washed as in the former case. The process is repeated until the slips of copper cease to be stained in the slightest degree—until, in short, the whole arsenic or antimony has been withdrawn.
The alkaline liquid contains the arsenic, as arsenate of potassium; the antimony, if present, as antimonate; and the solution is also contaminated by a little hydrated copper oxide; this latter separates on boiling, and can be filtered off, and the filtrate is boiled down to a small bulk. The liquid is washed into a small distillation-flask with strong hydrochloric acid, ferrous chloride is added, the flask, fitted with a safety tube, is connected with a condenser, and the arsenic distilled into water. To obtain the last traces of arsenic it may be necessary to distil it twice in this way, adding, each time, fresh strong acid and distilling to dryness. The distillate is then tested for arsenic by adding an equal bulk of saturated SH2 water. The sulphide of arsenic may be dealt with as described (p. 573).
The residue in the flask is now tested for antimony by saturating with SH2; should antimony be present, the precipitate by SH2 will probably be dark coloured, because of a small quantity of copper. The precipitate is collected, dissolved in dilute caustic soda, boiled, filtered to remove copper sulphide, the filtrate acidified by hydrochloric acid, and sulphuretted hydrogen water added. If antimony was present, this time the precipitate will be of an orange colour, and may be dealt with as described (p. 589).
The test experiments with regard to this combined process appear satisfactory.
§ 739. Arsenic in Glycerin.—Arsenic has been frequently found in commercial glycerin, the quantity varying from 0·1 to 1 mgrm. in 100 c.c. The best method to detect the presence of arsenic in glycerin is as follows:—A mixture of 5 c.c. of hydrochloric acid (1: 7) and 1 grm. of pure zinc is placed in a long test-tube, the mouth of which is covered with a disc of filter-paper previously moistened with one or two drops of mercuric chloride solution, and dried. If arsenic is present, a yellow stain is produced upon the filter-paper within fifteen minutes, and it subsequently becomes darker.767
§ 740. Arsenic in Organic Matters.—Orfila and the older school of chemists took the greatest care, in searching for arsenic, to destroy the last trace of organic matter. Orfila’s practice was to chop up the substance and make it into a paste with 400 to 700 grms. of water; to this ·010 grm. KHO in alcohol was added, and ·020 grm. of potassic nitrate. The substances were heated up to from 80° to 90° for some time, until they were pretty well dissolved; the organic matter was then burnt off in a Hessian crucible heated to redness, on which small quantities of the matters were placed at a time. When the whole had thus been submitted to red heat, the melted mass was run into an almost red-hot porcelain basin, and allowed to cool. Afterwards, it was again heated with concentrated sulphuric acid, until all nitric and nitrous fumes were dissipated; on dissolving and filtering in water, the liquid was introduced into a Marsh’s apparatus. Orfila never seems to have failed in detecting arsenic by this process. For an organ like the liver, he considered that 100 grms. of potash and 86 of strong sulphuric acid were necessary in order to destroy the organic matters.
The liability of the various reagents used to impurity, and the probability of loss in these operations, have tended to discredit destruction of the organic matter by a red heat, and chemists generally have preferred to oxidise animal matters by a moist process. The organic substance is divided finely and digested with dilute hydrochloric acid, and from time to time crystals of potassic chlorate are thrown in until all the fluid is very thin and capable of passing through a filter. The filtrate must now be submitted to the prolonged action of sulphuretted hydrogen,768 and the sulphide of arsenic separated from free sulphur by dissolving in sodic sulphide. After filtering, the arsenic sulphide may be again thrown down by the addition of hydrochloric acid, collected on a filter, and still further purified by solution in ammonic carbonate; once more precipitated by hydrochloric acid, and lastly identified by conversion into magnesia pyro-arseniate (see p. 572). The above process is a general and safe way of detecting arsenic in almost any organic tissue, but the author prefers the distillation process described p. 575 et seq.
From ordinary pills, quack extracts, and similar preparations, drying, powdering, and exhaustion with boiling dilute HCl, will remove the whole of the arsenic, if in a soluble state.
Oils and matters consisting almost entirely of fat, suspected of containing arsenic, are gently heated, and allowed to deposit any insoluble matter they may contain; the oil is then decanted, and, if necessary, filtered from any deposit; saponified by alcoholic potash, the soap decomposed by HCl, the fatty acids separated, and the arsenic looked for both in the first deposit and in the solution, now fairly free from fat, and easy to treat.
In searching for arsenic in the fluids or tissues of the body, the analyst is generally at the mercy of the pathologist, and sometimes the work of the chemist leads to a negative result, solely from not having the proper organ sent to him.769
Brodie long ago stated that when arsenious acid had been given in solution to any animal capable of vomiting, no arsenic could be detected in the stomach; this statement is too absolute, but in the majority of cases true.
In all cases the chemist should have portions of the brain, spinal cord, liver, kidneys, lungs, and muscular tissue, as well as the stomach and its contents.
According to the experiments of Scolosuboff,770 arsenic is generally greatest in the marrow, then in the brain, next in the liver, and least in the muscles, and the following may be taken as a fairly accurate statement of the relative proportion in which arsenic is likely to be found in the body, 100 grms. being taken of each:—
| Muscles, | 1 | |
| Liver, | 10 | ·8 |
| Brain, | 36 | ·5 |
| Spinal Marrow, | 37 | ·3 |
But Ludwig’s771 experiments and conclusions are entirely opposed to this, since both in acute and chronic cases he found as follows (per cent. As2O3):—
| Brain, | ·0002 |
| Liver, | ·001 |
| Kidney, | ·0004 |
| Muscle, | ·00025 |
So that he detected in the liver five times more than in the brain. M. P. Hamberg has also confirmed the fact, that more is found in the liver and kidneys than in the nervous tissues.
Chittenden772 found in a body the following quantities of arsenic estimated as arsenious acid:—
| Grain. | |
|---|---|
| Stomach and gullet, | 0·158 |
| Intestines, | 0·314 |
| Liver, | 0·218 |
| Kidney, | 0·029 |
| Lungs and spleen, | 0·172 |
| Heart, | 0·112 |
| Brain, | 0·075 |
| Diaphragm, | 0·010 |
The whole arsenic present was estimated as equal to 3·1 grains of arsenious acid, viz., 2·628 grains absorbed, and 0·472 unabsorbed; of the absorbed portion 8·3 per cent. was found in the liver.
With regard to the preliminary treatment of the stomach and fluids submitted to the analyst, the careful noting of appearances, the decantation, washing, and examination773 (microscopical and chemical) of any deposit, are precautions so obviously dictated by common sense, that they need only be alluded to in passing. Of some considerable moment is the question which may be put to the analyst in court, in reference to the possible entrance of arsenic into the living body, by accidental and, so to speak, subtle means. Such are the inhaling of the fumes from the burning of arsenical candles,774 and of emanations from papers (see p. 541),[775] as well as the possible entrance of arsenic into the body after death from various sources, such as arsenical earth, &c.776
§ 741. Imbibition of Arsenic after Death.—The arguments which are likely to be used, in favour of a corpse having become arsenical may be gathered from a case related by Sonnenschein:—Certain bodies were exhumed in two churchyards; the evidence went to show that they had been poisoned by arsenic, and this substance was actually found in the bodies, while at the same time it was discovered to exist also in traces in the earth of the churchyard. The theory for the defence was, that although the arsenic in the earth was in an insoluble state, yet that it might combine with lime as an arsenite of lime; this arsenite would become soluble by the action of carbonic acid set free by vegetation, and filter down to the corpse. Sonnenschein suspended a quantity of this earth in water, and passed CO2 through it for twelve hours; on filtering, the liquid gave no evidence of arsenic. A similar result was obtained when an artificial mixture of 1 grm. of arsenious acid and 1 pound of earth were submitted to the same process.
The fact would appear to stand thus: oxide of iron in ordinary earth retains arsenic, and requires treatment with a concentrated acid to dissolve it. It therefore follows that, if a defence of arsenical earth is likely to be set up, and the analyst finds that by mere extraction of the tissues by water he can detect arsenic, the defence is in all probability unsound. The expert should, of course, deal with this question on its merits, and without prejudice. According to Eulenberg,777 in arsenical earth—if, after having been crushed and washed, it lies for some time exposed to the disintegrating action of the air—soluble arsenical salts are formed, which may find their way into brooks and supplies of drinking water. We may infer that it is hardly probable (except under very peculiar circumstances) for a corpse to be contaminated internally with an estimable quantity of arsenic from the traces of arsenic met with in a few churchyards.
It occasionally happens that an exhumation is ordered a very long time after death, when no organs or parts (save the bones) are to be distinguished. In the case of a man long dead, the widow confessing that she had administered poison, the bones were analysed by Sonnenschein, and a small quantity of arsenic found. Conièrbe and Orfila have both asserted that arsenic is a normal constituent of the bones—a statement which has been repeatedly disproved. Sonnenschein relates:778—“I procured from a churchyard of this place (Berlin) the remnants of the body of a person killed twenty-five years previously, and investigated several others in a similar way, without finding the least trace of arsenic. Similar experiments in great number were repeated in my laboratory, but in no case was arsenic recognised.” The opinion of the expert, should he find arsenic in the bones, must be formed from the amount discovered, and other circumstances.
A difficult case on which to form an opinion is one recorded by William P. Mason,779 as follows:—
The deceased, a farmer, bachelor, sixty-five years of age, and in good health, was taken violently sick shortly after breakfast, with vomiting and distress in the stomach. Although a physician was summoned, the symptoms increased in severity, and a little after midnight death ensued. The funeral took place three days later. Certain very damaging pieces of circumstantial evidence having been collected, the housekeeper was arrested on the charge of murder, it having been shown, among other things, that on the day preceding the death she had purchased an ounce of white arsenic.
Thirty-five days after death (from March 20 to April 25) the body was exhumed, and found in a state of remarkable preservation, and free from cadaveric smell. The stomach presented evidences of inflammation.
Portions sent for analysis were the stomach, portion of intestine, portion of liver, one kidney, and the heart. Arsenic was found in all these parts. White octahedral crystals were found in the contents of the stomach, which on separation gave arsenical reaction.
The arsenic found was:—
| Stomach and intestine, | 0·2376 | grm. |
| Liver and kidney, | 0·0032 | „ |
| Heart, | 0·0007 | „ |
| Total as metallic arsenic, | 0·2415 | „ |
The amount of arsenic recovered and produced in court was in quantity sufficient to produce death. Some time after the analytical report was made to the coroner, it was learned that an embalming fluid, highly arsenical in character, had been used upon the body by the undertaker at the time of preparation for burial. No injection of this embalming fluid was practised, but cloths wrung out in the fluid were laid upon the face and chest, and were kept constantly wet therewith during a period of many hours. In all about two quarts of embalming fluid were so used. Its composition appeared to be a strongly acidified solution of sodium arsenite and zinc sulphate. Only the arsenic and zinc were determined quantitatively, and they were found to be, zinc (metallic), 1·978 per cent., and arsenic (metallic), 1·365 per cent. by weight. An amount of this fluid measuring 15·7 c.c. would thus contain a weight of arsenic equal to that actually recovered from the body.
Extended medical testimony was offered by the prosecution, tending to show that, under the given circumstances, no fluid of any kind could have reached the stomach through the nose or mouth after death, thus anticipating what the defence afterwards claimed, that the undertaker was responsible for the arsenic discovered in the remains.
In order to gather further light upon the possibility of cadaveric imbibition of embalming fluid through the unbroken skin, test was made for zinc in the heart and stomach, and distinct traces of the metal were found in each instance. That at least a portion of the arsenic found in the body was due to post-mortem causes was thus distinctly proven. A weighed portion (62 grms.) of the stomach and contents was then most carefully analysed quantitatively for both zinc and arsenic with the following results:—Arsenic, 0·0648 grm., and zinc, 0·0079 grm. Bearing in mind the relative quantities of the two metals in the embalming fluid, it will be seen that the arsenic found in the 62 grms. of the stomach was nearly twelve times larger than it should have been to have balanced the zinc which was also present. This fact, together with the discovery of crystals of white arsenic in the stomach, constituted the case for the prosecution, so far as the chemical evidence was concerned.
The defence made an unsuccessful effort to show that the crystals of the tri-oxide originated from the spontaneous evaporation of the embalming fluid. The prosecution met this point by proving that such fluid had been abundantly experimented upon by exposure to a very low temperature during an interval of several months, and also by spontaneous evaporation with a view of testing that very question, and that the results had in every case been negative. Special importance was given these experiments, because of the well-known separation of octahedral crystals during the spontaneous evaporation of a hydrochloric acid solution of the white oxide, it having also appeared that, in the manufacture of the embalming fluid, the arsenic was used as white arsenic.
A very strong point was finally raised for the defence by the inability of the expert on the side of the prosecution to state positively whether or not an embalming fluid of the above composition would diffuse as a whole through dead tissue, or its several parts would be imbibed at different rates of speed, the zinc portion becoming arrested by albuminoid material and being therefore outstripped by the arsenic, or vice versa. The prisoner was ultimately acquitted.
In a case which occurred in the Western States of America, there was good reason for believing that arsenic had been introduced into the corpse of a man after his decease. With regard to the imbibition of arsenic thus introduced, Orfila780 says:—“I have often introduced into the stomach (as well as the rectum) of the corpses of men and dogs 2 to 3 grms. of arsenious acid, dissolved in from 400 to 500 grms. of water, and have examined the different viscera at the end of eight, ten, or twenty days. Constantly I have recognised the effects of cadaveric imbibition. Sections of the liver or other organs which touch the digestive canal, carefully cut and analysed, furnished arsenic, which could not be obtained sensibly (or not at all) from sections which had not been in contact with this canal. If the corpse remained long on the back after arsenious acid had been introduced into the stomach, I could obtain this metal from the left half of the diaphragm and from the inferior lobe of the left lung, whilst I did not obtain it from other portions of the diaphragm nor from the right lung.” Dr. Reece has also made some experiments on the imbibition of arsenic after death. He injected solutions of arsenious acid into the stomach of various warm-blooded animals, and found at various periods arsenic, not alone in the intestinal canal, but also in the spleen, liver, and kidneys.
§ 742. Analysis of Wall-Paper for Arsenic.—The separation of arsenic from paper admits of great variety of manipulation. A quick special method is as follows:—The paper is saturated with chlorate of potash solution, dried, set on fire in a suitable plate, and instantly covered with a bell-glass. The ash is collected, pulverised, and exhausted with cold water, which has previously thoroughly cleansed the plate and bell-glass; the arsenic in combination with the potash is dissolved, whilst oxides of chromium, copper, aluminium, tin, and lead remain in the insoluble portion.781
Fresenius and Hintz782 have elaborated a method for the examination of wall-papers, fabrics, yarns, and similar substances, which, provided the reagents are pure, is accurate and easy. Twenty-five grms. of the substance are placed in a half-litre distilling flask or retort, and 250 c.c. of HCl, specific gravity 1·19, added; after digestion for an hour, 5 c.c. of a saturated solution of ferrous chloride are added, and the liquid slowly distilled until frothing stops any farther distillation. A further quantity of 100 c.c. HCl is then added, and distilled over. The receiver, in each case, contains water, and must be kept cool. The united distillates are diluted to 800 c.c. and saturated with SH2. The arsenious sulphide is collected on an asbestos filter. After partial washing, it is heated with bromine in HCl of 1·9 specific gravity, and the solution again distilled with ferrous chloride. The distillate, on now being treated with SH2, gives arsenious sulphide free from organic matter.
§ 743. Estimation of Arsenic.—Most of the methods for the quantitative determination of arsenic are also excellent tests for its presence. It may be regarded, indeed, as an axiom in legal chemistry, that the precise amount of every substance detected, if it can be weighed or estimated by any process whatever, should be accurately stated. Indefinite expressions, such as “a small quantity was found,” “traces were detected,” &c., are most objectionable. The more perfect of the methods of evolving arsenic can be made quantitative. For example, the galvanic process introduced by Bloxam may be utilised as follows:—A fractional part of the arsenical solution is taken for the experiment; the bottom of a narrow-necked bottle of about 100 c.c. capacity is removed, and replaced by a piece of vegetable parchment. The neck of the bottle carries a cork, which is pierced by (1) a platinum wire, which is attached to a platinum electrode; (2) a short tube, bent at right angles, and connected by piping with a longer tube, which has also a rectangular bend, and dips into a solution of silver nitrate; (3) an ordinary funnel-tube, reaching nearly to the bottom. The bottle is placed in a beaker of such a size as to leave a small interval between the two, and the whole apparatus stands in a large vessel of cold water. Dilute sulphuric acid is now put into the bottle, and also into the beaker, so that the fluid reaches exactly the same level in each. The positive platinum electrode of a battery of six of Grove’s cells, or other efficient combination, is immersed in the liquid outside the bottle, connection with the negative plate is established, and hydrogen very soon comes off, and passes over into the nitrate of silver solution. When all the air is expelled, a portion of the rectangular tube is heated to redness, and if there is no stain nor any reduction of the silver, the acid is pure. If the gas is passed for a long time into the silver solution, the silver will be reduced to some extent by the hydrogen, although arsenic-free;783 so that it is better to rely upon the metallic ring or stain, which is certain to be formed on heating a portion of the tube red-hot, and keeping it at that temperature for at least ten minutes. The liquid is then passed through the funnel in successive portions; if arsenic is present, there will be a decided metallic ring on heating the tube as before, and if antimony is present, there will also be a stain; the distinctions between these stains have been described at p. 557.
The tube is kept red-hot until the stain is very distinct; then the source of heat is removed, and the gas allowed to bubble through the argentic nitrate solution, which it decomposes, as before detailed (p. 526). This process is continued until, on placing the delivery tube in a sample of clear nitrate of silver solution, there is no darkening of colour. In certain cases this may take a long time, but the apparatus, once set to work, requires little superintendence. At the conclusion, the whole of the arsenic is separated,—part is in the silver solution as arsenious acid, part in the tube as a ring of metallic arsenic. The portion of the tube containing the metallic arsenic should be cut off with a file and weighed, the arsenic then removed and re-weighed; the loss is the metal approximately. Or, the weight of the film may be estimated by having a set of similar deposits of known weight or quantities, in tubes exactly corresponding to those used in the analysis, and comparing or matching them.
The arsenious acid in the nitrate of silver may be dealt with in several ways. The equation given (p. 526) shows clearly that pure arsine, passed into nitrate of silver solution, decomposes it in such a manner that, if either the silver deposited or the free acid is estimated, the quantity of arsenic can from such data be deduced. In operating on organic liquids, ammonia and other products may be given off, rendering either of the indirect processes inadvisable. A very convenient method, applicable in many cases, is to throw out the silver by hydrochloric acid, alkalise the filtrate by bicarbonate of soda, and titrate with iodine solution. The latter is made by dissolving exactly 12·7 grms. of pure dry iodine by the aid of 18 grms. of potassic iodide in one litre of water, observing that the solution must take place in the cold, without the application of heat. The principle of the titration is, that arsenious acid, in the presence of water and free alkali, is converted into arsenic acid—
As2O3 + 4I + 2Na2O = As2O5 + 4NaI.
The end of the reaction is known by adding a little starch-paste to the solution; as soon as a blue colour appears, the process is finished.
Another convenient way by which (in very dilute solutions of arsenious acid) the arsenic may be determined, is a colorimetric method, which depends on the fact that sulphuretted hydrogen, when arsenious acid is present in small quantity, produces no precipitate at first, but a yellow colour, proportionate to the amount of arsenic present. The silver solution containing arsenious acid is freed from silver by hydrochloric acid; a measured quantity of saturated SH2 water is added to a fractional and, if necessary, diluted portion, in a Nessler cylinder or colorimetric apparatus, and the colour produced exactly imitated, by the aid of a dilute solution of arsenious acid, added from a burette to a similar quantity of SH2 water in another cylinder, the fluid being acidified with HCl.
§ 744. Destruction of the Organic Matter by Nitric Acid, and Subsequent Reduction of the Arsenic Acid to Arsine (Arseniuretted Hydrogen), and final Estimation as Metallic Arsenic.—This process, which is essentially a combination of several, has been much improved in its details by R. H. Chittenden and H. H. Donaldson.784 100 grms. of the suspected matters, cut up into small pieces, are heated in a porcelain dish of suitable size, stirred by means of a glass rod with 23 c.c. of pure concentrated nitric acid, and heated up to from 150° to 160°. When the matters assume a yellow or orange colour, the bath is removed from the source of heat, and 3 c.c. of pure concentrated sulphuric acid added, and the mixture stirred, when the mass becomes brown, swells up, and evolves dense nitrous and other fumes. The vessel is again heated to 180°, and while hot 8 c.c. of pure concentrated nitric acid are added, drop by drop, with continual stirring. After this addition, it is heated to 200° for fifteen minutes, and the result on cooling is a hard carbonaceous residue wholly free from nitric acid. The arsenic is in this way oxidised into arsenic acid, which is easily soluble in water. The contents of the dish are, therefore, perfectly extracted by boiling water, the aqueous extract filtered, and evaporated to dryness. The next process is to obtain the arsenic in a metallic state:—
The flask, a Bunsen’s wash-bottle of 200 c.c. capacity, is provided with a small separating funnel of 65 c.c. capacity, with glass stop-cock. This is a very material aid to the obtaining of a slow and even evolution of gas, an important desideratum when all loss is to be avoided; for with only a funnel tube, every time a small portion of fluid is added, a sudden rush of gas takes place, with probably a small, but still more or less appreciable, loss. But the separating funnel, filled with the acid mixture, can be so arranged as to give a constant and regular supply of fluid at the rate of two or three drops per minute, more or less. The gas generated is dried by a calcic chloride tube, and then passes through a tube of hard glass, heated to a red heat by a miniature furnace of three Bunsen lamps with spread burners, so that a continuous flame of 6 inches is obtained, and with a proper length of cooled tube not a trace of arsenic passes by. The glass tube where heated is wound with a strip of wire gauze, both ends being supported upon the edges of the lamp frame, so that the tube does not sink down when heated. The small furnace is provided with two appropriate side pieces of sheet metal, so that a steady flame is always obtained. When the quantity of arsenic is very small, the tube is naturally so placed that the mirror is deposited in the narrow portion; but when the arsenic is present to the extent of 0·005 grm., the tube should be 6 mm. in inner diameter, and so arranged that fully 2 inches of this large tube are between the flame and the narrow portion. When the quantity of arsenic is less, the tube can naturally be smaller.
Acids of different strengths are made as follows:—
| Acid No. 1. | |
| 545 | c.c. pure conc. H2SO4. |
| 5000 | c.c. H2O. |
| Acid No. 2. | |
| 109 | c.c. pure conc. H2SO4. |
| 1640 | c.c. Acid No. 1. |
| Acid No. 3. | |
| 218 | c.c. pure conc. H2SO4. |
| 1640 | c.c. Acid No. 1. |
| Acid No. 4. | |
| 530 | c.c. pure conc. H2SO4. |
| 1248 | c.c. H2O. |
25 to 35 grms. of granulated zinc, previously alloyed with a small quantity of platinum, are placed in the generator, and everything being in position, the apparatus is filled with hydrogen by the use of a small quantity of acid No. 2. After a sufficient time has elapsed, the gas is lighted at the jet, and the glass tube heated to a bright redness.
The arsenical solution in concentrated form is mixed with 45 c.c. of acid No. 2, and the mixture passed into the separating funnel, from which it is allowed to flow into the generator at such a rate that the entire fluid is introduced in one hour or one and a half; 40 c.c. of acid No. 3 are then added and allowed to flow slowly into the generator, and, lastly, 45 c.c. of acid No. 4. The amount of time required will vary with the amount of arsenic: 2 to 3 mgrms. of arsenic will require about two to three hours for the entire decomposition, while 4 to 5 mgrms. will need perhaps three to four hours. Where the amount of arsenic is small, only 25 grms. of zinc are needed, and but 45 c.c. of acid No. 2, 30 c.c. of acid No. 3, and 30 c.c. of acid No. 4; but when 4 to 5 mgrms. of arsenic are present, it is better to take the first mentioned quantities of zinc and acids.
The arsenic being thus collected as a large or small mirror of metal, the tube is cut at a safe distance from the mirror, so that a tube of perhaps 2 to 6 grms. weight is obtained. This is carefully weighed, and then the arsenic removed by simple heating; or, if the arsenic is to be saved (as in a toxicological case), dissolved out with strong nitric acid. The tube is then cleaned, dried, and again weighed, the difference giving the weight of metallic arsenic, from which, by a simple calculation, the amount of arsenious oxide can be obtained. Some test results are given as follows; they were obtained by introducing definite quantities of arsenious oxide in the form of a solution mixed with 45 c.c. of No. 2 acid, &c.:—
| Quantity of Arsenic introduced. | Wt. of Metallic Arsenic found. | Theoretical Wt. of Metallic Arsenic. | ||
|---|---|---|---|---|
| 0·005 | grm. | As2O3 | 0·00373 | 0·00378 |
| 0·005 | „ | „ | 0·00370 | 0·00378 |
| 0·004 | „ | „ | 0·00300 | 0·00303 |
| 0·002 | „ | „ | 0·00151 | 0·00151 |
Sanger estimates and tests for minute quantities of arsenic by the Marsh-Berzelius process, and uses a generator of hydrogen; that is to say, the hydrogen is evolved in the ordinary way from zinc and sulphuric acid, and the issuing gas dried by calcic chloride; but into this flask is also delivered from another flask, charged with sulphuric acid and zinc, pure hydrogen, so that into the second flask, little by little, may be added the solution to be tested; and, owing to the generating flask, the gas may be made to give a uniform current, and at the end of the operation all arsine swept out. To estimate the quantities of arsenic in the gas, the reduction tube is heated, and a mirror or mirrors obtained, and compared with a set of standard mirrors. The standard mirrors are made as follows:—One grm. of arsenious oxide, purified by repeated sublimation, is dissolved with the aid of a little sodic bicarbonate, and, after acidification with dilute sulphuric acid, made up to 1 litre. This standard solution contains 1 mgrm. of As2O3 in every c.c., and is used to make a second standard solution, containing 0·01 mgrm., to every c.c., by diluting 10 c.c. to a litre. Of this last solution, 1 c.c., 2 c.c., 3 c.c., and so on, are measured and introduced into the reduction flask, and the standard mirrors obtained. It is recommended, for obvious reasons, to make more than one standard for each quantity, for the appearance of the mirrors from the same amount of arsenic varies. The tubes are hermetically sealed, and, when not in use, kept in the dark.
This process is convenient for small amounts of arsenic; but, as stated before, the results are given as metallic arsenic, whereas the films appear never to be composed of pure metallic arsenic, but a mixture of hydride and suboxide. Test experiments give, however, fair results.785
§ 745. Arsine Developed from an Alkaline Solution.—Fleitmann discovered in 1851 that arsenic, mixed with finely divided zinc, and excess of soda or potash added, evolved arsine; but no stibine was evolved under the same conditions. In 1873 J. W. Gatehouse suggested the use of aluminium and sodic hydrate as a modification of Fleitmann’s test, for the purpose of distinguishing between arsenic and antimony; and this is now the usual process adopted. The hydrogen comes off regularly even in the cold, but it is best to apply a little heat. This test will evolve arsine from arsenious acid, and also from arsenic trisulphide; but it is not available for the detection of arsenic, when the arsenic is in the form of arsenic acid. According to Clark,786 it is not adapted for quantitative purposes, because, owing to the formation of solid hydride, about one-fifth remains behind.
E. W. Davy, in 1876, proposed the use of sodium amalgam for the generation of arsine; on the whole, it is, however, not so convenient as the aluminium process.
The liquid to be tested is made strongly alkaline with pure sodic or potassic hydrate placed in a flask connected with a tube dipping into a 4 per cent. solution of silver nitrate, a few pieces of sheet aluminium added, and the flask gently heated; any arsine present will reduce the silver. The silver solution thus blackened may be treated in the manner described (p. 567).
§ 746. Precipitation as Tersulphide.—Despite the advantages of some of the processes described, which are (to a certain extent) easy and accurate, not a few chemists still prefer the old method of precipitation with hydric sulphide SH2, because, although tedious, it has stood the test of experience. If this be used, it is well in most cases to pass sulphurous anhydride through the liquid until it smells strongly of the gas, for by this means any arsenic acid present is reduced, the sulphurous anhydride is quickly got rid of by a current of carbonic anhydride, and then the liquid is saturated with hydric sulphide. In the ordinary way, much time is often wasted in saturating the liquid with this gas. Those, however, who have large laboratories, and daily employ hydric sulphide, possess (or should possess) a water saturated with the gas under pressure; such a liquid, added in equal volume to an arsenical solution, is able to convert the whole of the arsenic into sulphide in a very few minutes. Those who do not possess this hydric sulphide water can saturate in an hour the liquid to be tested, by passing the gas in under pressure.787 A convenient method is to evolve SH2 from sulphide of antimony and ClH; the gas passes first into a wash-bottle, and then into a strong flask containing the solution under trial. This flask is furnished with a safety-valve, proportioned to the strength of the apparatus; the two tubes dipping into the wash-bottle and the last flask are provided with Bunsen’s valves, which only allow the gas to pass in one direction. The hydric sulphide is then driven over by heat, and when sufficient gas has in this way passed into the liquid, the flame is withdrawn, and the apparatus allowed to stand for some hours, the valves preventing any backward flow of the liquid or gas. When the precipitate has settled to the bottom, the supernatant fluid is carefully passed through a filter, and the precipitate washed by decantation in the flask, without transference to the filter, if it can be avoided.
The impure sulphide is washed with water, then with alcohol, then with carbon disulphide, then, after having got rid of the lead, again with alcohol, and finally with water; it is then dissolved in ammonia, the ammonia solution filtered, and the filtrate evaporated to dryness on a sand-bath, at a somewhat high temperature; in this way it is freed from sulphur and, to a great extent, from organic matter; after weighing, it may be purified or identified by some of the following methods:—
(a) Solution in Ammonia and Estimation by Iodine.788—The filter is pierced, the sulphide washed into a flask by ammonia water (which need not be concentrated), and dissolved by warming, filtered from any insoluble matter, and estimated by iodine and starch.
(b) Oxidation of the Sulphide and Precipitation as Ammonia Magnesian Arseniate, or Magnesia Pyro-Arseniate.—The tersulphide, as before, is dissolved in ammonia (not omitting the filter-paper, which should be soaked in this reagent), the solution filtered, and evaporated to dryness. The dry residue is now oxidised by fuming nitric acid, taking care to protect the dish with a large watch-glass (or other cover) during the first violent action; the dish is then heated in the water-bath until all the sulphur has disappeared, and only a small bulk of the liquid remains; it is then diluted and precipitated by “magnesia mixture.”789 The fluid must stand for several hours, and, if the arsenic is to be determined as the usual ammoniacal salt, it must be passed through a weighed filter, and washed with a little ammoniacal water (1: 3). The solubility of the precipitate is considerable, and for every 16 c.c. of the filtrate (not the washings) 1 mgrm. must be allowed. The precipitate, dried at 100°, 2(NH4MgAsO4)H2O, represents 39·47 per cent. metallic arsenic.
| Sulphate of magnesia, | 1 |
| Chloride of ammonium, | 1 |
| Solution of ammonia, | 4 |
| Water, | 8 |
Dissolve; then allow to stand for several days; finally filter, and keep for use.
The solubility of the magnesium arseniate itself, and the general dislike which chemists have to weighing in such hygroscopic material as a filter, are, perhaps, the main reasons for the variation of this old method, which has lately come into notice. Rose proposed some time ago the conversion of the double salt into the pyro-arseniate—a method condemned by Fresenius and Parnell, but examined and pronounced a practicable and accurate process by Remol, Rammelsberg, Thorpe, Fuller, Wittstein, Emerson, Macivor, Wood, and Brauner. The modification of Rose’s process, recommended by Wood,790 and still further improved by Brauner,791 may be accepted.
The precipitation is effected by magnesia mixture, with the addition of half its bulk of alcohol. The solution is allowed to stand for several hours, until it is possible to decant the clear liquid from the precipitate; the latter is now dissolved in ClH, reprecipitated as before, thrown on a small filter, and washed with a mixture of one volume of ammonia, two volumes of alcohol, and three of water.
The precipitate is now dried, and transferred as completely as possible from the filter into a small porcelain crucible, included in a larger one made of platinum, moistened with nitric acid, covered and heated at first gently, lastly to a bright redness; the filter is then treated similarly, and the crucible with its contents weighed. Pyro-arseniate of arsenic (Mg2As2O7) contains 48·29 per cent. of metallic arsenic.
(c) Conversion of the Trisulphide of Arsenic into the Arsenomolybdate of Ammonia.—The purified sulphide is oxidised by nitric acid, the acid solution is rendered alkaline by ammonia, and then precipitated by a molybdenum solution, made as follows:—100 grms. of molybdic acid are dissolved in 150 c.c. of ordinary ammonia and 80 of water; this solution is poured drop by drop into 500 c.c. of pure nitric acid and 300 c.c. of water; it is allowed to settle, and, if necessary, filtered. The molybdic solution must be mixed in excess with the liquid under treatment, the temperature raised to 70° or 80°, and nitric acid added in excess until a yellow coloration appears; the liquid is then passed through a tared filter, and dried at 100°. It contains 5·1 per cent. of arsenic acid [3·3 As].792
(d) Conversion of the Sulphide into Metallic Arsenic.—If there should be any doubt as to the nature of the precipitated substances, the very best way of resolving this doubt is to reduce the sulphide to metal; the easiest method of proving this is to dissolve in potash and obtain arsine by the action of aluminium; or if it is desired to evolve arsine from an acid solution with zinc in the usual way, then by dissolving a slight excess of zinc oxide in potash or soda, and dissolving in this the arsenic sulphide; the zinc combines with all the sulphur, and converts the sulpharsenite into arsenite; the zinc sulphide is filtered off, and the filtrate acidified and introduced into Marsh’s apparatus. The original process of Fresenius was to mix the sulphide with carbonate of soda and cyanide of potassium, and place the mixture in the wide part of a tube of hard German glass, drawn out at one end to a capillary fineness. Carbonic anhydride, properly dried, was passed through the tube, and the portion containing the mixture heated to redness; in this way the arsenical sulphide was reduced, and the metal condensed in the capillary portion, where the smallest quantity could be recognised. A more elaborate and accurate process, based on the same principles, has been advocated by Mohr.793
A convenient quantity of carbonate of soda is added to the sulphide, and the whole mixed with a very little water, and gently warmed. The yellow precipitate is very soon dissolved, and then the whole is evaporated carefully, until it is in a granular, somewhat moist, adhesive state. It is now transferred to a glass tube, open at top and bottom, but the top widened into a funnel; this tube is firmly held perpendicularly on a glass plate, and the prepared sulphide hammered into a compact cylinder by the aid of a glass rod, which just fits the tube. The cylinder is now dried over a flame, until no more moisture is to be detected, and then transferred into a glass tube 4 or 5 inches long, and with one end drawn to a point (the weight of this tube should be first accurately taken). The tube is connected with the following series:—(1) A chloride of calcium tube; (2) a small bottle containing nitrate of silver solution; (3) a hydrogen-generating bottle containing zinc and sulphuric acid. The hydrogen goes through the argentic nitrate solution, leaving behind any sulphur and arsenic it may contain; it is then dried by chloride of calcium, and streams in a pure dry state over the cylinder of prepared sulphide (no error with regard to impurities in the gas is likely to occur; but in rigid inquiries it is advisable to heat a portion of the tube, previous to the insertion of the cylinder, for some time, in order to prove the absence of any external arsenical source); when it is certain that pure hydrogen, unmixed with air, is being evolved, the portion of the tube in which the cylinder rests is heated slowly to redness, and the metallic arsenic sublimes at a little distance from the source of heat. Loss is inevitable if the tube is too short, or the stream of hydrogen too powerful.
The tube after the operation is divided, the portion soiled by the soda thoroughly cleansed, and then both parts weighed; the difference between the weight of the empty tube and the tube + arsenic gives the metallic arsenic. This is the process as recommended by Mohr; it may, however, be pointed out that the glass tube itself loses weight when any portion of it is kept red-hot for some little time; and, therefore, unless the crust is required in the original tube, it is better to divide it, carefully weigh the arsenical portion, remove the crust, and then re-weigh. The method is not perfectly accurate. The mirror is not pure metallic arsenic (see p. 571), and if the white alkaline residue be examined, arsenic will be detected in it, the reason being that the arsenical sulphide generally contains pentasulphide of arsenic as well as free sulphur. Now the pentasulphide does not give up metallic arsenic when treated as before detailed; nor, indeed, does the trisulphide, if mixed with much sulphur, yield an arsenical crust. It is, therefore, of great moment to free the precipitate as much as possible from sulphur, before attempting the reduction.
The development of a reducing gas from a special and somewhat complicated apparatus is not absolutely necessary. The whole process of reduction, from beginning to end, may take place in a single tube by any of the following processes:—(1) The sulphide is mixed with oxalate of soda (a salt which contains no water of crystallisation), and the dry mixture is transferred to a suitable tube, sealed at one end. An arsenical mirror is readily obtained, and, if the heat is continued long enough, no arsenic remains behind—an excellent and easy method, in which the reducing gas is carbonic oxide, in an atmosphere of carbonic anhydride. (2) The sulphide is oxidised by aqua regia, and the solution evaporated to complete dryness. The residue is then dissolved in a few drops of water, with the addition of some largish grains of good wood charcoal (which absorb most of the solution), and the whole carefully dried. The mass is now transferred to a tube closed at one end, a little charcoal added in the form of an upper layer, and heat applied first to this upper layer, so as to replace the air with CO2, and then to bring the whole tube gradually to redness from above downwards. In this case also the whole of the arsenic sublimes as a metallic mirror.
There are various other modifications, but the above are trustworthy, and quite sufficient. Brugelmann’s method of determining arsenic, elsewhere described, would appear to possess some advantages, and to promise well; but the writer has had no personal experience of it with regard to arsenic.
§ 747. Conversion of Arsenic into Arsenious Chloride (AsCl3).—This process, first employed by Schneider and Fyfe, and afterwards modified by Taylor, differs from all the preceding, since an attempt is made to separate by one operation volatile metallic chlorides, and to destroy the organic matter, and thus obtain two liquids—one a distillate—tolerably clear and free from solid particles, whilst the mass in the retort retains such metals as copper, and is in every way easy to deal with.
Schneider and Fyfe employed sulphuric acid and common salt; but Taylor recommends hydrochloric acid, which is in every respect preferable. As recommended by Taylor, all matters, organic or otherwise, are to be completely desiccated before their introduction into a retort, and on these dried substances sufficient pure hydrochloric acid poured, and the distillation pushed to dryness. Every one is well aware how tedious is the attempt to dry perfectly the organs of the body (such as liver, &c.) at any temperature low enough to ensure against volatilisation of such a substance as, e.g., calomel. This drying has, therefore, been the great stumbling-block which has prevented the general application of the process. It will be found, however, that drying in the ordinary way is by no means necessary. The writer cuts up the solid organ (such as liver, brain, &c.) with scissors into small pieces, and transfers them to a retort fitted by an air-tight joint to a Liebig condenser; the condenser in its turn being connected with a flask by a tube passing through an india-rubber stopper dipping into a little water. Another tube from the same flask is connected with india-rubber piping, which is connected with a water-pump, the fall tube of which terminates in the basement of a house over a gully. The distillation is now carried on to carbonisation; on cooling, a second quantity of hydrochloric acid is added, and the last fraction of the distillate examined for arsenic. If any is found, a third distillation is necessary. At the termination of the operation the retort is washed with water, the solution filtered, and this solution and the distillate are each separately examined for arsenic. If properly performed, however, the second distillation brings over the whole of the arsenical chloride,794 and none will be found in the retort. With the above arrangement there can be no odour, nor is there any loss of substance. In the distillate the arsenic can hardly be in the form of arsenious chloride, but rather arsenious acid and hydrochloric acid; for the chloride easily splits up in the presence of water into these substances. It is best to convert it into the trisulphide. Taylor795 recommends evolving arsine in the usual way, and passing the arsine (AsH3) into solution of silver nitrate, finally estimating it as an arseniate of silver. Objections with regard to the impurity of reagents should be met by blank experiments. Kaiser796 has proposed and practised a modification of this method, which essentially consists in the use of sulphuric acid and sodic chloride (as in Schneider and Fyfe’s original process), and in passing the distillate first into a flask containing a crystal or two of potassium chlorate, and thence into an absorption bulb; in the latter most of the arsenic is found in the form of arsenic acid, the chloride having been oxidised in its passage. The apparatus is, however, complicated in this way without a corresponding advantage.797 Lastly, E. Fischer798 has shown that it is a considerable advantage to add from 10 to 20 c.c. of a saturated solution of ferrous chloride before distilling with HCl. In this way all the arsenic, whether as arsenic or arsenious acids, is easily converted into chloride.
2. Antimony
§ 748. Metallic Antimony.—Atomic weight, 120·3 (R. Schneider), 120·14 (Cook799); specific gravity, 6·715; fusing-point about 621° (1150° F.). In the course of analysis, metallic antimony may be seen as a black powder thrown down from solutions; as a film deposited on copper or platinum; and, lastly, as a ring on the inside of a tube from the decomposition of stibine. At a bright red-heat it is volatilised slowly, even when hydrogen is passed over it; chlorine, bromine, and iodine combine with it directly. It may be boiled in concentrated ClH without solution; but aqua regia, sulphides of potassium and sodium readily dissolve it. The distinction between thin films of this metal and of arsenic on copper and glass are pointed out at pp. 557 and 559. It is chiefly used in the arts for purposes of alloy, and enters to a small extent into the composition of fireworks (vide pp. 534 and 581).
§ 749. Antimonious Sulphide.—Sulphide of antimony = 336; composition in 100 parts, Sb 71·76, S 28·24. The commercial article, known under the name of black antimony, is the native sulphide, freed from silicious matter by fusion, and afterwards pulverised. It is a crystalline metallic-looking powder, of a steel-grey colour, and is often much contaminated with iron, lead, copper, and arsenic.
The amorphous sulphide (as obtained by saturating a solution of tartar emetic with SH2) is an orange-red powder, soluble in potash and in ammonic, sodic, and potassic sulphides; and dissolving also in concentrated hydrochloric acid with evolution of SH2. It is insoluble in water and dilute acid, scarcely dissolves in carbonate of ammonia, and is quite insoluble in potassic bisulphite. If ignited gently in a stream of carbonic acid gas, the weight remains constant. To render it anhydrous, a heat of 200° is required.
The recognition of arsenic in the commercial sulphide is most easily effected by placing 2 grms. or more in a suitable retort (with condenser), adding hydrochloric acid, and distilling. The chloride of arsenic passes over before the chloride of antimony; and by not raising the heat too high, very little antimony will come over, even if the distillation be carried almost to dryness. The arsenic is detected in the distillate by the ordinary methods.
Several lamentable accidents have happened through mistaking the sulphide of antimony for oxide of manganese, and using it with potassic chlorate for the production of oxygen. The addition of a drop of hydrochloric acid, it is scarcely necessary to say, will distinguish between the two.
Antimony is frequently estimated as sulphide. An amorphous tersulphide of mercury, containing a small admixture of antimonious oxide and sulphide of potassium, is known under the name of Kermes mineral, and has lately been employed in the vulcanising of india-rubber. Prepared in this way, the latter may be used for various purposes, and thus become a source of danger. It behoves the analyst, therefore, in searching for antimony, to take special care not to use any india-rubber fittings which might contain the preparation.
A pentasulphide of antimony (from the decomposition of Schleppe’s salt [Na3Sb6S4 + 9H2O], when heated with an acid) is used in calico-printing.
§ 750. Tartarated Antimony, Tartrate of Potash and Antimony, or Tartar Emetic, is, in a medico-legal sense, the most important of the antimonial salts. Its formula is KSbC4H4O7H2O, and 100 parts, theoretically, should contain 35·2 per cent. of metallic antimony. The B.P. gives a method of estimation of tartar emetic not free from error, and Professor Dunstan has proposed the following:—Dissolve 0·3 grm. of tartar emetic in 80 c.c. of water, add to this 10 c.c. of a 5 per cent. solution of sodium bicarbonate, and immediately titrate with a decinormal solution of iodine, using starch as an indicator. One c.c. of n⁄10 iodine = 0·0166 grm. tartar emetic; therefore, if pure, the quantity used by 0·3 grm. should be 18 c.c. Tartar emetic occurs in commerce in colourless, transparent, rhombic, octahedral crystals, slightly efflorescing in dry air.
A crystal, placed in the subliming cell (p. 258), decrepitates at 193·3° (380° F.), sublimes at 248·8° (480° F.) very slowly and scantily, and chars at a still higher temperature, 287·7° (550° F.). On evaporating a few drops of a solution of tartar emetic, and examining the residue by the microscope, the crystals are either tetrahedra, cubes, or branched figures. 100 parts of cold water dissolve 5 of tartar emetic, whilst the same quantity of boiling water dissolves ten times as much, viz., 50. The watery solution decomposes readily with the formation of algæ; it gives no precipitate with ferrocyanide of potassium, chloride of barium, or nitrate of silver, unless concentrated.
§ 751. Metantimonic Acid, so familiar to the practical chemist from its insoluble sodium salt, is technically applied in the painting of glass, porcelain, and enamels; and in an impure condition, as antimony ash, to the glazing of earthenware.
§ 752. Pharmaceutical, Veterinary, and Quack Preparations of Antimony.800
(1) Pharmaceutical Preparations:—
Oxide of Antimony (Sb2O3) is a white powder, fusible at a low red heat, and soluble without effervescence in hydrochloric acid, the solution responding to the ordinary tests for antimony. Arsenic may be present in it as an impurity; the readiest means of detection is to throw small portions at a time on glowing charcoal, when very small quantities of arsenic will, under such conditions, emit the peculiar odour. Carbonate of lime appears also to have been found in the oxide of commerce.
Antimonial Powder is composed of one part of oxide of antimony and two parts of phosphate of lime; in other words, it ought to give 33·3 per cent. of Sb2O3.
Tartar Emetic itself has been already described. The preparations used in medicine are—
The Wine of Antimony (Vinum antimoniale), which is a solution of tartar emetic in sherry wine, and should contain 2 grains of the salt in each ounce of the wine (0·45 grm. in 100 c.c.).
Antimony Ointment (Unguentum antimonii tartarati) is a mechanical mixture of tartar emetic and lard, or simple ointment;801 strength 20 per cent. There is no recorded case of conviction for the adulteration of tartar emetic; cream of tartar is the only probable addition. In such a case the mixture is less soluble than tartar emetic itself, and on adding a small quantity of carbonate of soda to a boiling solution of the suspected salt, the precipitated oxide at first thrown down, becomes redissolved.
Solution of Chloride of Antimony is a solution of the terchloride in hydrochloric acid; it is a heavy liquid of a yellowish-red colour, powerfully escharotic; its specific gravity is 1·47; on dilution with water, the whitish-yellow oxychloride of antimony is precipitated. One drachm (3·549 c.c.) mixed with 4 ounces (112 c.c.) of a solution of tartaric acid (·25: 4) gives a precipitate with SH2, which weighs at least 22 grains (1·425 grm.). This liquid is used on very rare occasions as an outward application by medical men; farriers sometimes employ it in the foot-rot of sheep.
Purified Black Antimony (Antimonium nigrum purificatum) is the purified native sulphide Sb2S3; it should be absolutely free from arsenic.
Sulphurated Antimony (Antimonium sulphuratum) is a mixture of sulphide of antimony, Sb2S3, with a small and variable amount of oxide, Sb2O3. The P.B. states that 60 grains (3·888 grms.) dissolved in ClH, and poured into water, should give a white precipitate of oxychloride of antimony, which (properly washed and dried) weighs about 53 grains (3·444 grms.). The officinal compound pill of subchloride of mercury (Pilula hydrargyri subchloridi composita) contains 1 grain (·0648 grm.) of sulphurated antimony in every 5 grains (·324 grm.), i.e., 20 per cent.
(2) Patent and Quack Pills:—
Dr. J. Johnson’s Pills.—From the formula each pill should contain:—
| Grains. | Grms. | |||
|---|---|---|---|---|
| Compound Extract of Colocynth, | 2 | ·5 | = | ·162 |
| Calomel, | ·62 | = | ·039 | |
| Tartar Emetic, | ·04 | = | ·002 | |
| Oil of Cassia, | ·12 | = | ·007 | |
| 3 | ·28 | = | ·210 | |
The oil of cassia can be extracted by petroleum ether; the calomel sublimed and identified by the methods given in the article on “Mercury”; the antimony deposited in the metallic state on platinum or tin; and the colocynth extracted by dissolving in water, acidifying, and shaking up with chloroform. On evaporating the chloroform the residue should taste extremely bitter; dissolved in sulphuric acid it changes to a red colour, and dissolved in Fröhde’s reagent to a cherry-red. It should also have the ordinary reactions of a glucoside.
Mitchell’s Pills contain in each pill:—
| Grains. | Grms. | |||
|---|---|---|---|---|
| Aloes, | 1 | ·1 | = | ·070 |
| Rhubarb, | 1 | ·6 | = | ·103 |
| Calomel, | ·16 | = | ·010 | |
| Tartar Emetic, | ·05 | = | ·003 | |
| 2 | ·91 | = | ·186 | |
The mineral substances in this are easy of detection by the methods already given; the aloes by the formation of chrysammic acid, and the rhubarb by its microscopical characters.
Dixon’s Pills probably contain the following in each pill:—
| Grains. | Grms. | |||
|---|---|---|---|---|
| Compound Extract of Colocynth, | 2 | ·0 | = | ·1296 |
| Rhubarb, | 1 | ·0 | = | ·0648 |
| Tartar Emetic, | ·06 | = | ·0038 | |
| 3 | ·06 | = | ·1982 | |
(3) Antimonial Medicines, chiefly Veterinary:802—
Liver of Antimony is a preparation formerly much used by farriers. It is a mixture of antimonious oxide, sulphide of potassium, carbonate of potassium, and undecomposed trisulphide of antimony (and may also contain sulphate of potassium), all in very undetermined proportions. When deprived of the soluble potash salts, it becomes the washed saffron of antimony of the old pharmacists. A receipt for a grease-ball, in a modern veterinary work, gives, with liver of antimony, cream of tartar and guaiacum as ingredients.
Hind’s Sweating-ball is composed of 60 grains (3·888 grms.) of tartar emetic and an equal portion of assafœtida, made up into a ball with liquorice-powder and syrup. The assafœtida will be readily detected by the odour, and the antimony by the methods already recommended.
Ethiops of Antimony, very rarely used now, is the mechanical mixture of the sulphides of antimony and mercury—proportions, 3 of the former to 2 of the latter.
The Flowers of Antimony is an impure oxysulphide of antimony, with variable proportions of trioxide and undecomposed trisulphide.
Diaphoretic Antimony (calcined antimony) is simply antimoniate of potash.
Glass of Antimony is a mixture of sulphide and oxide of antimony, contaminated with a small quantity of silica and iron.
A quack pill, by name, Ward’s Red Pill, is said to contain glass of antimony and dragon’s blood.
Antimonial Compounds used in Pyrotechny:—
| Blue Fire:— | ||
| Antimonious sulphide, | 1 | |
| Sulphur, | 2 | |
| Nitre, | 6 | |
This composition is used for the blue or Bengal signal-light at sea. Bisulphide of carbon and water are solvents which will easily separate the powder into its three constituents.
| Crimson Fire:— | |||
| Potassic Chlorate, | 17· | 25 | |
| Alder or Willow Charcoal, | 4· | 5 | |
| Sulphur, | 18· | ||
| Nitrate of Strontia, | 55· | ||
| Antimonious Sulphide, | 5· | 5 | |
The spectroscope will readily detect strontia and potassium, and the analysis presents no difficulty. In addition to these a very great number of other pyrotechnical preparations contain antimony.
§ 753. Alloys.—Antimony is much used in alloys. The ancient Pocula emetica, or everlasting emetic cups, were made of antimony, and with wine standing in them for a day or two, they acquired emetic properties. The principal antimonial alloys are Britannia and type metal, the composition of which is as follows:—
| Tin, per cent. | Copper, per cent. | Antimony, per cent. | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Britannia Metal, | Best, | 92 | ·0 | 1 | ·8 | 6 | ·2 | |||
| Common, | 92 | ·1 | 2 | ·0 | 5 | ·9 | ||||
| For Castings, | 92 | ·9 | 1 | ·8 | 5 | ·3 | ||||
| For Lamps, | 94 | ·0 | 1 | ·3 | 4 | ·7 | ||||
| Tea Lead, per cent. | Antimony, per cent. | Block Tin, per cent. | ||||||||
| Type Metal, | - | (1.) | 75 | 20 | 5 | |||||
| (2.) | 70 | 25 | 5 | |||||||
| Metal for Stereotype, | 84 | ·2 | 13 | ·5 | 2 | ·3 | ||||
There is also antimony in brass, concave mirrors, bell-metal, &c.
§ 754. Pigments.—Cassella and Naples yellow are principally composed of the antimoniate of lead.
Antimony Yellow is a mixture of antimoniate of lead with basic chloride of lead.
§ 755. Dose.—A medicinal dose of a soluble antimonial salt should not exceed 97·2 mgrms. (11⁄2 grain). With circumstances favouring its action, a dose of 129·6 mgrms. (2 grains) has proved fatal;803 but this is quite exceptional, and few medical men would consider so small a quantity dangerous for a healthy adult, especially since most posological tables prescribe tartar emetic as an emetic in doses from 64·8 to 194·4 mgrms. (1 to 3 grains). The smallest dose which has killed a child appears to be 48·5 mgrms. (3⁄4 grain).804 The dose of tartar emetic for horses and cattle is very large, as much as 5·832 grms. (90 grains) being often given to a horse in his gruel three times a day. 3·8 grms. (60 grains) are considered a full, but not an excessive, dose for cattle; ·38 grm. (6 grains) is used as an emetic for pigs, and half this quantity for dogs.
§ 756. Effects of Tartar Emetic and of Antimony Oxide on Animals.—Large doses of tartar emetic act on the warm-blooded animals as on man; whether the poison is taken by the mouth, or injected subcutaneously, all animals able to vomit805 do so. The heart’s action, at first quickened, is afterwards slowed, weakened, and lastly paralysed. This action is noticed in cold as well as in warm-blooded animals. It is to be ascribed to a direct action on the heart; for if the brain and spinal cord of the frog be destroyed—or even if a solution of the salt be applied direct to the frog’s heart separated from the body—the effect is the same. The weak action of the heart, of course, causes the blood-pressure to diminish, and the heart stops in diastole. The voluntary muscles of the body are also weakened; the breathing is affected, partly from the action on the muscles. The temperature of the body is depressed (according to F. A. Falck’s researches) from 4·4° to 6·2°.
The effect of small doses given repeatedly to animals has been several times investigated. Dr. Nevin806 experimented upon eleven rabbits, giving them tartar emetic four times a day in doses of 32·4 mgrms. (1⁄2 grain), 64·8 mgrms. (1 grain), and 129·6 mgrms. (2 grains). Five died, the first after four, the last after seventeen days; three were killed after one, three, and four days respectively, two after an interval of fourteen days, and one thirty-one days after taking the last dose. There was no vomiting; diarrhœa was present in about half the number; one of the rabbits, being with young, aborted. The chief symptoms were general dulness, loss of appetite, and in a few days great emaciation. Four of the five that died were convulsed before death, and several of the animals exhibited ulcers of the mucous membrane of the mouth, in places with which the powder had come in contact. Caillol and Livon have also studied the action of small doses of the white oxide of antimony given in milk to cats. A cat took in this way in 109 days ·628 grm. The animal passed gradually into a cachectic state, diarrhœa supervened, and it died miserably thin and exhausted.
§ 757. Effects of Tartar Emetic on Man.807—The analogy between the symptoms produced by arsenic and antimony is striking, and in some acute cases of poisoning by tartar emetic, there is but little (if any) clinical difference. If the dose of tartar emetic is very large, there may be complete absence of vomiting, or only a single evacuation of the stomach. Thus, in a case mentioned by Taylor, in which a veterinary surgeon swallowed by mistake 13 grms. (200 grains) of tartar emetic, vomiting after fifteen minutes could only be induced by tickling the throat. So, again, in the case reported by Mr. Freer, a man, aged 28, took 7·77 grms. (120 grains) of tartar emetic by mistake for Epsom salts; he vomited only once; half an hour after taking the poison he had violent pain in the stomach and abdomen, and spasmodic contraction of the abdomen and arms; the fingers were firmly contracted, the muscles quite rigid, and there was involuntary aqueous purging. After six hours, during which he was treated with green tea, brandy, and decoction of oak-bark, he began to recover, but suffered for many nights from profuse perspirations.
With more moderate and yet large doses, nausea and vomiting are very prominent symptoms, and are seldom delayed more than half an hour. The regular course of symptoms may therefore be summed up thus:—A metallic taste in the mouth, repeated vomitings, which are sometimes bloody, great faintness and depression, pains in the abdomen and stomach, and diarrhœa, which may be involuntary. If the case is to terminate fatally, the urine is suppressed, the temperature falls, the face becomes cyanotic, delirium and convulsions supervene, and death occurs in from two to six days. Antimony, like arsenic, often produces a pustular eruption. Solitary cases deviate more or less from the course described, i.e., severe cramps affecting all the muscles, hæmorrhage from the stomach, kidney, or bowel, and death from collapse in a few hours, have all been noticed. In a case recorded by Mr. Morley,808 a surgeon’s daughter, aged 18, took by mistake an unknown quantity of antimonial wine; she soon felt sleepy and powerless, and suffered from the usual symptoms in combination with tetanic spasms of the legs. She afterwards had enteritis for three weeks, and on recovery her hair fell off. Orfila relates a curious case of intense spasm of the gullet from a large dose of tartar emetic.
§ 758. Chronic Antimonial Poisoning.—The cases of Palmer and J. P. Cook, M. Mullen, Freeman, Winslow, Pritchard, and the remarkable Bravo case have, in late years, given the subject of chronic antimonial poisoning a considerable prominence. In the trials referred to, it was shown that medical men might easily mistake the effects of small doses of antimony given at intervals for the action of disease—the symptoms being great nausea, followed by vomiting, chronic diarrhœa, alternating with constipation, small frequent pulse, loss of voice, great muscular weakness, depression, with coldness of the skin and a clammy perspiration. In the case of Mrs. Pritchard,809 her face was flushed, and her manner so excited as to give an ordinary observer the idea that she had been drinking; and with the usual symptoms of vomiting and purging, she suffered from cramps in the hands. Dr. Pritchard tried to make it appear that she was suffering from typhoid fever, which the symptoms in a few respects only resembled.
According to Eulenberg, workmen, exposed for a long period to the vapour of the oxide of antimony, suffer pain in the bladder and a burning sensation in the urethra, and continued inhalation even leads to impotence and wasting of the testicles.810
§ 759. Post-mortem Appearances.—The effect of large doses of tartar emetic is mainly concentrated upon the gastro-intestinal mucous membrane. There is an example in the museum of University College Hospital of the changes which resulted from the administration of tartar emetic in the treatment of pneumonia. These are ascribed in the catalogue, in part to the local action of the medicine, and in part to the extreme prostration of the patient. In the preparation (No. 1052) the mucous membrane over the fore border of the epiglottis and adjacent part of the pharynx has been destroyed by sloughing; the ulceration extends into the upper part of the œsophagus. About an inch below its commencement, the mucous membrane has been entirely removed by sloughing and ulceration, the circular muscular fibres being exposed. Above the upper limit of this ulcer, the mucous membrane presents several oval, elongated, and ulcerated areas, occupied by strips of mucous membrane which have sloughed. In other places, irregular portions of the mucous membrane, of a dull ashen-gray colour, have undergone sloughing; the edges of the sloughing portion are of colours varying from brown to black.
It is seldom that so much change is seen in the gullet and pharynx as this museum preparation exhibits; but redness, swelling, and the general signs of inflammation are seldom absent from the stomach and some parts of the intestines. On the lining membrane of the mouth, ulcers and pustules have been observed.
In Dr. Nevin’s experiments on the chronic poisoning of rabbits already referred to, the post-mortem appearances consisted in congestion of the liver in all the rabbits; in nearly all there was vivid redness of the stomach; in two cases there was ulceration; in some, cartilaginous hardness of the pylorus; while, in others, the small intestines presented patches of inflammation. In two of the rabbits the solitary glands throughout the intestines were prominent, yellow in colour, and loaded with antimony. The colon and rectum were healthy, the kidneys congested; the lungs were in most congested, in some actually inflamed, or hepatised and gorged with blood. Bloody extravasations in the chest and abdomen were frequent.
Saikowsky,811 in feeding animals daily with antimony, found invariably in the course of fourteen to nineteen days fatty degeneration of the liver, and sometimes of the kidney and heart. In the experiment of Caillol and Livon also all the organs were pale, the liver had undergone fatty degeneration, and the lung had its alveoli filled with large degenerated cells, consisting almost entirely of fat. The mesenteric glands also formed large caseous masses, yellowish-white in colour, which, under the microscope, were seen to be composed of fatty cells, so that there is a complete analogy between the action of arsenic and antimony on the body tissues.
§ 760. Elimination of Antimony.—Antimony is mainly eliminated by the urine. In 1840, Orfila showed to the Académie de Médecine metallic antimony, which he had extracted from a patient who had taken ·12 grm. of tartar emetic in twenty-four hours. He also obtained antimony from an old woman, aged 80, who twelve hours before had taken ·6 grm. (91⁄4 grains)—a large dose, which had neither produced vomiting nor purging. In Dr. Kevin’s experiments on rabbits, antimony was discovered in the urine after the twelfth dose, and even in the urine of an animal twenty-one days after the administration of the poison had been suspended.
§ 761. Antidotes for Tartar Emetic.—Any infusion containing tannin or allied astringent principles, such as decoctions of tea, oak-bark, &c., may be given with advantage in cases of recent poisoning by tartar emetic, for any of the salt which has been expelled by vomiting may in this way be decomposed and rendered harmless. The treatment of acute poisoning which has proved most successful, has been the encouraging of vomiting by tickling the fauces, giving strong green tea and stimulants. (See Appendix.)
§ 762. Effects of Chloride or Butter of Antimony.—Only a few cases of poisoning by butter of antimony are on record: its action, generally speaking, on the tissues is like that of an acid, but there has been considerable variety in the symptoms. Five cases are recorded by Taylor; three of the number recovered after taking respectively doses of 7·7 grms. (2 drachms) and 15·5 grms. (4 drachms), and two died after taking from 56·6 to 113 grms. (2 to 4 ounces). In one of these cases the symptoms were more like those of a narcotic poison, in the other fatal case there was abundant vomiting with purging. The autopsy in the first case showed a black appearance from the mouth to the jejunum, as if the parts had been charred, and extensive destruction of the mucous membrane. In the other case there were similar changes in the stomach and the upper part of the intestines, but neither the lips nor the lower end of the gullet were eroded. In a case recorded by Mr. Barrington Cooke,812 a farmer’s wife, aged 40, of unsound mind, managed to elude the watchfulness of her friends, and swallowed an unknown quantity of antimony chloride about 1.30 P.M. Shortly afterwards she vomited several times, and had diarrhœa; at 2.30 a medical man found her lying on her back insensible, and very livid in the face and neck. She was retching, and emitting from her mouth a frothy mucous fluid, mixed with ejected matter of a grumous colour; the breathing was laboured and spasmodic; the pulse could not be felt, and the body was cold and clammy. She expired at 3.30, about one hour and a half from the commencement of symptoms, and probably within two hours from the taking of the poison. The autopsy showed no corrugation of the tongue or inner surface of the lining membrane of the mouth, and no appearance of the action of a corrosive upon the lips, fauces, or mucous membrane of the œsophagus. The whole of the mucous membrane of the stomach was intensely congested, of a dark and almost black colour, the rest of the viscera were healthy. Chemical analysis separated antimony equivalent to nearly a grm. (15 grains) of the chloride, with a small quantity of arsenic, from the contents of the stomach.
§ 763. Detection of Antimony in Organic Matters.—In acute poisoning by tartar emetic it is not impossible to find a mere trace only in the stomach, the greater part having been expelled by vomiting, which nearly always occurs early, so that the most certain method is, where possible, to analyse the ejected matters. If it should be suspected that a living person is being slowly poisoned by antimony, it must be remembered that the poison is mainly excreted by the kidneys, and the urine should afford some indication. The readiest way to test is to collect a considerable quantity of the urine (if necessary, two or three days’ excretion), concentrate by evaporation, acidify, and then transfer the liquid to a platinum dish, in which is placed a slip of zinc. The whole of the antimony is in time deposited on the platinum dish, and being thus concentrated, may be subsequently identified in any way thought fit.
Organic liquids are boiled with hydrochloric acid; organic solids are extracted with the same acid in the manner described (p. 51); or, if the distillation process given at p. 576 be employed, the antimony may be found partly in the distillate, and partly in the retort. In any case, antimony in solution may be readily detected in a variety of ways—one of the most convenient being to concentrate on tin or platinum, to dissolve out the antimonial film by sulphide of ammonium, and thus produce the very characteristic orange sulphide.
If a slip of pure tinfoil be suspended for six hours in a solution, which should not contain more than one-tenth of its bulk of ClH, and exhibit no stain or deposit, it is certain that antimony cannot be present. It may also conveniently be deposited on a platinum dish,813 by filling the same with the liquid properly acidulated, and inserting a rod of zinc; the metallic antimony can afterwards be washed, dried, and weighed.
Reinsch’s and Marsh’s tests have been already described (pp. 558 and 559), and require no further notice. There is, however, a very beautiful and delicate means of detecting antimony, which should not be omitted. It is based upon the action of stibine (SbH3) on sulphur.814 When this gas is passed over sulphur, it is decomposed according to equation, 2SbH3 + 6S = Sb2S3 + 3SH2, the action taking place slowly in diffused daylight, but very rapidly in sunshine. An ordinary flask for the evolution of hydrogen (either by galvanic processes or from zinc and sulphuric acid), with its funnel and drying-tubes, is connected with a narrow tube having a few fragments of sulphur, kept in place by plugs of cotton wool. The whole apparatus is placed in sunshine; if no orange colour is produced when the hydrogen has been passing for some time, the liquid to be tested is poured in gradually through the funnel, and if antimony should be present, the sulphur acquires a deep orange colour. This is distinct even when so small a quantity as ·0001 grain has been added through the funnel. The sulphide of antimony thus mixed with sulphur can, if it is thought necessary, be freed from the sulphur by repeated exhaustion with bisulphide of carbon. The stibine does not, however, represent all the antimony introduced, a very large proportion remaining in the evolution flask;815 hence it cannot be employed for quantitative purposes. Moreover, the test can, of course, only be conveniently applied on sunny days, and is, therefore, in England more adapted for summer.816 Often, however, as mentioned elsewhere, when the analyst has no clue whatever to the nature of the poison, it is convenient to pass SH2 in the liquid to saturation.817 In such a case, if antimony is present (either alone or in combination with other sulphides), it remains on the filter, and must be separated and identified as follows:—The sulphides are first treated with a solution of carbonate of ammonia, which will dissolve arsenic, if present, and next saturated in situ with pure sulphide of sodium, which will dissolve out sulphide of antimony, if present. The sulphide of antimony will present the chemical characters already described, more particularly—
(1) It will evolve SH2 when treated with HCl, and at the same time pass into solution.818
(2) The solution evaporated to get rid of free HCl gives with water a thick cheesy precipitate of basic chloride of antimony. This may be seen if only a drop or two of the solution be taken and tested in a watch-glass.
(3) If tartaric acid be added to the solution, this precipitation does not occur.
(4) The solution from (3) gives an orange precipitate with SH2.
Such a substance can only be sulphide of antimony. With regard to (2), bismuth would act similarly, but under the circumstances could not be present, for the sulphide of bismuth is insoluble in sodic sulphide.
§ 764. Quantitative Estimation.—The quantitative estimation of antimony is best made by some volumetric process, e.g., the sulphide can be dissolved in HCl, some tartrate of soda added, and then carbonate of soda to weak alkaline reaction. The strength of the solution of tartarised antimony thus obtained can now be estimated by a decinormal solution of iodine, the end reaction being indicated by the previous addition of a little starch solution, or by a solution of permanganate of potash, either of which should be standardised by the aid of a solution of tartar emetic of known strength.
3. Cadmium
§ 765. Cadmium, Cd = 112; specific gravity, 8·6 to 8·69; fusing-point, 227·8° (442° F.); boiling-point, 860° (1580° F.).—Cadmium in analysis is seldom separated as a metal, but is estimated either as oxide or sulphide.
§ 766. Cadmium Oxide, CdO = 128—cadmium, 87·5 per cent.; oxygen, 12·5 per cent.—is a yellowish or reddish-brown powder, non-volatile even at a white heat; insoluble in water, but dissolving in acids. Ignited on charcoal, it is reduced to metal, which volatilises, and is then deposited again as oxide, giving to the coal a distinct coat of an orange-yellow colour in very thin layers; in thicker layers, brown.
§ 767. Cadmium Sulphide, CdS = 144—Cd, 77·7 per cent.; S, 22·3 per cent.—known as a mineral termed Greenockite. When prepared in the wet way, it is a lemon-yellow powder, which cannot be ignited in hydrogen without loss, and is insoluble in water, dilute acids, alkalies, alkaline sulphides, sulphate of soda, and cyanide of potassium. The solution must not contain too much hydrochloric acid, for the sulphide is readily soluble with separation of sulphur in concentrated hydrochloric acid. It may be dried in the ordinary way at 100° without suffering any decomposition.
§ 768. Medicinal Preparations.—The Iodide of Cadmium (CdI2) occurs in white, flat, micaceous crystals, melting at about 215·5° (419·9° F.), and at a dull red heat giving off violet vapour. In solution, the salt gives the reactions of iodine and cadmium. The ointment of iodide of cadmium (Unguentum cadmii iodidi) contains the iodide in the proportion of 62 grains to the ounce, or 14 per cent.
Cadmium Sulphate is officinal in the Belgian, Portuguese, and French pharmacopœias.
§ 769. Cadmium in the Arts, &c.—Cadmium is used in various alloys. The sulphide is found as a colouring ingredient in certain toilet soaps, and it is much valued by artists as a pigment. The iodide of cadmium is employed in photography, and an amalgam of metallic cadmium to some extent in dentistry.
§ 770. Fatal Dose of Cadmium.—Although no deaths from the use of cadmium appear to have as yet occurred, its use in photography, &c., may lead to accidents. There can be no question about the poisonous action of cadmium, for Marmé,819 in his experiments on it with animals, observed giddiness, vomiting, syncope, difficulty in respiration, loss of consciousness, and cramps. The amount necessary to destroy life can only be gathered from the experiments on animals. A strong hound died after the injection of ·03 grm. (·462 grain) subcutaneously of a salt of cadmium; rabbits are poisoned if from 19·4 to 38·8 mgrms. (·3 to ·6 grain) are introduced into the stomach. A watery solution of ·5 grm. (7·5 grains) of the bromide administered to a pigeon caused instant death, without convulsion; the same dose of the chloride killed a second pigeon in six minutes; ·25 grm. (3·85 grains) of sulphite of cadmium administered to a pigeon excited vomiting, and after two hours diarrhœa; it died in eight days. Another pigeon died from a similar dose in fourteen days, and cadmium, on analysis, was separated from the liver. From the above cases it would seem probable that 4 grms. (61·7 grains) would be a dangerous dose of a soluble salt of cadmium for an adult, and that in a case of chronic poisoning it would most probably be found in the liver.
§ 771. Separation and Detection of Cadmium.—If cadmium be in solution, and the solution is not too acid, on the addition of SH2 there is precipitated a yellow sulphide, which is distinguished from antimony and arsenical sulphides by its insolubility in ammonia and alkaline sulphides. Should all three sulphides be on the filter (an occurrence which will seldom, perhaps never, happen), the sulphide of arsenic can be dissolved out by ammonia, the antimony by sulphide of sodium, leaving the sulphide of cadmium as the residue.820
The further tests of the sulphide are:—
(1) It dissolves in dilute nitric acid to a colourless fluid, with separation of sulphur.
(2) The solution, filtered and freed from excess of nitric acid by evaporation, gives with a solution of ammonic carbonate a white precipitate of carbonate of cadmium insoluble in excess. This distinguishes it from zinc, which gives a similar white precipitate, but is soluble in the excess of the precipitant.
(3) The carbonate thus obtained, heated on platinum foil, is changed into the brown-red non-volatile oxide.
(4) The oxide behaves on charcoal as already detailed.
(5) A metallic portion can be obtained by melting the oxide with cyanide of potassium; it is between zinc and tin in brilliancy, and makes a mark on paper like lead, but not so readily. There are many other tests, but the above are conclusive.
If cadmium in any case be specially searched for in the organs or tissues, the latter should be boiled with nitric acid. The acid solution is filtered, saturated with caustic potash, evaporated to dryness, and ignited; the residue is dissolved in dilute hydrochloric acid, and treated after filtration with SH2. Cadmium may also be estimated volumetrically by digesting the sulphide in a stoppered flask with ferric chloride and hydrochloric acid; the resulting ferrous compound is titrated with permanganate, each c.c. of a d.n. solution of permanganate = ·0056 grm. of cadmium.
Notes
700 Fresenius has pointed out that sulphur may mask small quantities of arsenic, antimony, tin, &c., and he recommends that the turbid liquid in which apparently nothing but sulphur has separated should be treated as follows:—A test-tube is half filled with the liquid, and then a couple of c.c. of petroleum ether or of benzene added, the tube closed by the thumb, and the contents well shaken. The sulphur dissolves, and is held in solution by the solvent, which latter forms a clear upper layer. If traces of a metallic sulphide were mixed with the sulphur, thin coloured films are seen at the junction of the two layers, and the sulphides may also coat the tube above the level of the liquid with a slight faintly-coloured pellicle (Chem. News, Jan. 4, 1895).
701 Bull. de la Société Chem. de Paris, t. xx. 10, 1873.
702 Chem. Centrbl., 1889, 569.
703 N. Klobrikow, Zeit. Anal. Chem., xxix. 129-133.
704 L’Orosi, 1892, 397-411.
705 Die Arsenwasserstoff-Vergiftung, Archiv f. exper. Path. u. Pharm., Leipzig, 1882.
706 Trost, Vergiftung durch Arsenwasserstoff bei der technischen Gewinnung des Silbers, Vierteljahrsschrift f. gericht. Med., xviii. Bd., 2 Heft, S. 6, 1873.
707 Ambroise Tardieu, Étude Médico-légale sur l’Empoisonnement, Obs. xxv. p. 449.
708 The formula for arseniate of soda is Na2HAsO47H2O, but it sometimes contains more water.
709 The Venice turpentine is rarely found in ordinary commerce, what is sold under that name consisting of black resin and oil of turpentine.
710 A similar preparation in common use has the addition of sulphate of zinc.
711 Alum and carbonate of lead coloured with Brazil and peach woods.
712 Chevers, Med. Jurisprudence for India, p. 116.
713 P. Gucci, Chem. Centrbl., 1887, 1528.
714 The dust from the preserved skins of animals has caused, at least, one case of poisoning. Ann. d’Hyg. Pub. et de Méd. Lég., 2 sér., 1870, t. xxxiii, p. 314.
715 Commercial arsenic is often much adulterated, especially with gypsum, chalk, &c. These are most readily detected by subliming the arsenic. The sublimed arsenic itself may not be entirely pure, sometimes containing arsenical sulphides and antimonious oxide.
716 Annal. d. Chemie u. Pharmacie, Bd. cxxvii., H. 2, 243.
717 Cooley’s Dictionary, Art. “Arsenic.”
718 Archiv f. exper. Path. u. Pharmakol, Leipzig, 1882.
719 Étude Physiol. d’Arsène, Thèse, Paris, 1868.
720 Tardieu, op. cit.
721 Edin. Med. Journ., April 1865; Brit. and For. Med. Chir. Journ., Oct. 1865.
722 Phil. Trans., 1812.
723 “Gleanings in Toxicology,” by C. Meymott Tidy, M.B.—Lancet, Aug. 21, 1878.
724 Two recipes were handed in at the coroner’s inquest which pretty fairly represent the composition of ordinary commercial violet powder:—
725 Belloc, Méd. Lég., t. iv. p. 124.
726 Recueil de la Soc. de Méd. de Paris, t. vi. p. 22, An. vii.; also Tardieu, Étude Méd. Légale, sur l’Empoisonnement, Obs. xxvii. p. 457.
727 Mean, Bibliothèque Méd., t. lxxiv., 1821, p. 401.
728 Tardieu, op. cit., Obs. xxix.; Dr. Vernois, Ann. d’Hyg. et de Méd. Lég., t. xxxvi., 1st ser., p. 141, 1846.
729 Ansiaulx, Clinique Chirurgicale. Mangor (Acta. Societ. Reg. Hafniens, iii. p. 178) gives the case of a man who poisoned his three wives successively with arsenic—the two last by introducing into the vagina a powder composed of flour and arsenic. Another similar case is related by Brisken. Mangor made experiments on mares, showing that when arsenic is applied to the vagina, death may result from inflammation.
730 Méd. Légale, iv.
731 Vierteljahr. f. gericht Med., N. F., ix. 96.
732 Azione di alcune Muffe sui Compositi fissi d’Arsenico. Ministero dell’ Interno, Laboratori Scientifici della Direzione di Sanita, Roma, 1892.
733 “On the Formation of Volatile Compounds of Arsenic from Arsenical Wall-Papers,” American Academy of Arts and Sciences, vol. xxix.
734 Case 188 in Casper’s Handbuch.
735 Taylor’s Principles and Practice of Jurisprudence, vol. i. p. 251; Flandin, vol. i. p. 535.
736 Tardieu, op. cit., Obs. xix.
737 Tardieu, “Relation Médico-Légale de l’Assassinat de la Duchesse de Praslin,” Ann. d’Hyg. Pub. et de Médico-Lég., 1847, t. xxxviii. p. 390; also op. cit., Obs. xi.
738 Journal de Van der Monde, 1756, t. iv. p. 353; Tardieu, op. cit., Obs. xiii. p. 430.
739 “The Action of Poisons,” Phil. Trans., 1812.
740 Journ. de Médecine, 1783, p. 353; Tardieu, op. cit., Obs. xiv. p. 431.
741 Journ. de Connaiss. Méd. Chirurg., 1839, p. 155; Tardieu, op. cit., Obs. xv. p. 482.
742 Op. cit., Obs. xvii. p. 434.
743 Bouley (Jeune), Ann. d’Hyg. et de Médico-Lég., 1834, t. xii. p. 393.
744 Tome i. Obs. iv. p. 314.
745 “The Maybrick Trial and Arsenical Poisoning,” by Thos. Stevenson, M.D., Guy’s Hosp. Rep., 1889.
746 Beiträge zur Pathologie der acuten Arsenikvergiftung., Archiv für exper. Pathol. u. Pharmakol., Leipzig, 1882.
747 Tome i. Obs. v.
748 This preparation at the time of my visit had no number.
749 In a case related by Orfila, t. i. Obs. xv., death resulted from the outward application of arsenic; the mucous membrane of the stomach was natural in colour, but there were four ulcers, one of which was 50 centimetres in diameter.
750 Op. cit., Obs. i. p. 468.
751 Phil. Trans., 1812.
752 T. i. p. 319.
753 Handbuch, vol. ii. p. 420.
754 Zeit. physiol. Chem., xvii. 311-339.
755 Op. cit.
756 An old experiment of Orfila’s has some practical bearings, and may be cited here. A dog was treated by ·12 grm. of arsenious acid, and supplied plentifully with liquid to drink; his urine, analysed from time to time during ten days, gave abundant evidences of arsenic. On killing the animal by hanging on the tenth day, no arsenic could be detected in any of the organs of the body; it had been, as it were, washed out.
757 Otto recommends the first half of the drying tube connected with the development flask to be filled with caustic potash, the latter half with chloride of calcium (Ausmittelung der Gifte). Dragendorff approves of this, but remarks that it should be used when arsenic alone is searched for, since caustic potash decomposes stibine. The potash fixes SH2, and prevents the formation of chloride of arsenic; on the other hand, it absorbs some little AsH3.
758 For identification of arsenical films, see p. 557.
759 Blondlot, “Transformation de l’arsenic en hydrure solide par l’hydrogène aissant sous l’influence des composés nitreux.”—Jour. de Pharm. et de Chim., 3e sér., t. xliv. p. 486.
760 With regard to purity of reagents, Sonnenschein states that he has once found chlorate of potash contaminated with arsenic.—Sonnenschein, Gericht. Chemie, p. 139.
761 M. A. Gautier uses sulphuric acid diluted with five times its weight of water; when the hydrogen has displaced the air, he adds to the arsenical matter 45 grms. of this acid and 5 grms. of pure sulphuric acid.—Bull. de la Société Chim. de Paris, 1875, t. xxiv.
762 F. W. Schmidt, Zeit. anorg. Chem., i. 353-359.
763 It is desirable to dissolve away the free sulphur often deposited with the arsenical sulphide by bisulphide of carbon.
764 Schönbein has proposed ozone as an oxidiser of arsenical stains. The substance containing the stain, together with a piece of moist phosphorus, is placed under a shade, and left there for some time; the oxidisation product is, of course, coloured yellow by SH2 if it is arsenious acid, orange if antimony. The vapour of iodine colours metallic arsenic pale yellow, and later a brownish hue; on exposure to the air it loses its colour. Iodine, on the other hand, gives with antimony a carmelite brown, changing to orange.
An arsenical ring may be also treated as follows:—Precipitated zinc sulphide is made into a paste with a little water, and introduced into the end of the tube; the same end is then plunged into dilute sulphuric acid, and the ring heated, when the arsenical sulphide will be produced.
765 Journ. f. pract. Chem., xiii. 168.
766 Journ. Chem. Soc., June 1893, 886.
767 “Arsenic in Glycerin,” by Dr. H. B. H. Paul and A. J. Cownley, Pharm. Journ., Feb. 24, 1894.
768 The SH2 should be washed by passing it through two or more washing bottles supplied with warm dilute HCl—a few samples of sulphide of iron give off an arseniferous gas, so that this precaution is necessary.
769 For example, in cases of poisoning by external application, more than once merely the empty stomach and a piece of intestine have been forwarded to the writer.
770 Bull. Soc. Chim. (2), xxiv. p. 124.
771 Ueber die Verhaltung des Arsens im thierischen Organismus nach Einverleibung von Arseniger Säure. Med. Jahrbuch, 1880.
772 American Chemical Journal, v. 8.
773 From some observations of Fresenius in a recent number of the Zeitschrift f. anal. Chem., it would seem necessary to test all glass vessels used; for it is difficult at present to purchase arsenic-free glass.
774 See a case of poisoning (non-fatal) of a lady by the use of arsenical candles, Med. Times and Gazette, vol. iii., 1876, p. 367.
775 To solve this question, it has been at times considered necessary to analyse an extraordinary number of things. In the “affaire Danval” (Journ. d’Hygiène, 2e sér., No. 108, July 1878), more than sixty different articles, comprising drugs, drinks, perfumes, bed-curtains, wall-paper, and other matters, were submitted to the experts.
776 The following important case is related by Sonnenschein:—
Nicholas Nobel and his wife, Jerome, were buried two metres from each other in the churchyard at Spinal, the earth of which notoriously contained arsenic. A suspicion of poisoning arose. The bodies were exhumed, and arsenic was found in the stomach and intestines of Nobel, but not the slightest trace in the corpse of the wife. The remains of the bodies were reinterred, and after six months, on a fresh suspicion of poisoning arising, again exhumed. The corpse of the woman had been put naked in the moist earth during a heavy shower, but this time also no arsenic was detected in it.
777 Gewerbe Hygiene, p. 234.
778 Gerichtl. Chem., p. 212.
779 Chem. News, Feb. 23, 1894.
780 Op. cit., t. i. p. 309.
781 Kapferschlaeger: Rev. Universelle des Mines, 1876.
782 Zeit. anal. Chem., xxvii. 179-182.
783 Nitrate of silver solution is reduced by H2, CH3, PH3, and SbH3; hence it is absolutely necessary in any qualitative examination to prove that arsenious acid has actually been produced in the silver solution.
784 American Chem. Journ., vol. ii., No. 4; Chem. News, Jan. 1881, p. 21.
785 Proc. American Academy of Arts and Sciences, vol. xxvi.
786 Journ. Chem. Soc., 1893, 884.
787 Hydric sulphide gas has been liquefied, and is now an article of commerce, being sold in iron bottles.
788 P. Champion and H. Pellett, Bull. Soc. Chim. (2), xxvj. pp. 541-544.
789 Magnesia Mixture:—
790 Zeitschrift für anal. Chem., vol. xiv. p. 356.
791 Ibid., xvj. pp. 57, 58.
792 Champion and Pellett, Bull. Soc. Chim., Jan. 7, 1877.
793 Mohr’s Toxicologie, p. 57.
794 Dragendorff asserts to the contrary; but we may quote the authority of Taylor, who has made several experiments, in which he obtained all the arsenic as chloride. The writer has performed the process many times, each time carefully testing the mass in the retort for arsenic; but the result proved that it had entirely passed over.
795 Principles of Medical Jurisprudence, vol. i. p. 267.
796 Zeitschr. f. anal. Chem., xiv. pp. 250-281.
797 Selmi (Atti dell. Accademia dei Lincei, Fasc. ii., 1879) proposed a modification of Schneider’s process. The substances are treated with hot, pure sulphuric acid, and at the same time the liquid is traversed by a stream of hydrochloric acid gas. The resulting distillate is tested for arsenic by Marsh’s process. Selmi states that, operating in this way, he has detected 1⁄400 of a mgrm. of As2O3 in 100 grms. of animal matter.
798 Scheidung u. Bestimmung d. Arsens; Liebig’s Annalen d. Chemie, Bd. ccvii. p. 182.
799 Ann. Phys. Chem. (2), v. pp. 255-281.
800 The history of antimony as a drug is curious. Its use was prohibited in France in 1566, because it was considered poisonous, one Besnier being actually expelled from the faculty for transgressing the law on this point. The edict was repealed in 1650; but in 1668 there was a fresh enactment, confining its use to the doctors of the faculty.
801 Simple ointment is composed of white wax 2, lard 3, almond oil 3 parts.
802 There has long prevailed an idea (the truth of which is doubtful) that antimony given to animals improves their condition; thus, the Encyclop. Brit., 5th ed., art. “Antimony”:—“A horse that is lean and scrubby, and not to be fatted by any means, will become fat on taking a dose of antimony every morning for two months together. A boar fed for brawn, and having an ounce of antimony given him every morning, will become fat a fortnight sooner than others put into the stye at the same time, and fed in the same manner, but without the antimony.” Probably the writer means by the term antimony the impure sulphide. To this may be added the undoubted fact, that in Brunswick the breeders of fat geese add a small quantity of antimonious oxide to the food, as a traditional custom.
803 Taylor, Guy’s Hosp. Reports, Oct. 1857.
804 Op. cit.
805 L. Hermann (Lehrbuch der experimentellen Toxicologie) remarks that the vomiting must be considered as a reflex action from the inflammatory excitement of the digestive apparatus, especially of the stomach. It is witnessed if the poison is administered subcutaneously or injected into the brain. Indeed, it is established that (at least, so far as the muscles are concerned) the co-ordinated movements producing vomiting are caused by excitement of the medulla oblongata. Giannussi and others found that after section between the first and third vertebræ of dogs, and subsequent administration of tartar emetic, no vomiting took place; and Grimm’s researches seem to show that the suspected vomit-centre is identical with the respiratory centre, so that the vomiting movement is only an abnormal respiratory movement. L. Hermann, however, considers the theory that when tartar emetic is introduced into the vessels the vomit-centre is directly excited, erroneous, for (1) in introducing it by the veins much larger doses are required to excite vomiting than by the stomach; and (2), after subcutaneous injection of the salt, antimony is found in the first vomit. His explanation, therefore, is that antimony is excreted by the intestinal tract, and in its passage excites this action. Majendie’s well-known experiment—demonstrating that, after extirpation of the stomach, vomiting movements were noticed—is not considered opposed to this view.
806 Lever, Med. Chir. Journ., No. 1.
807 Antimony occasionally finds its way into articles of food through obscure channels. Dr. Page has recorded the fact of antimonial lozenges having been sold openly by an itinerant vendor of confectionery. Each lozenge contained nearly a quarter of a grain (·16 mgrms.), and they caused well-marked symptoms of poisoning in the case of a servant and two children. How the antimony got in was unknown. In this case it appears to have existed not as tartar emetic, but as an insoluble oxide, for it would not dialyse in aqueous solution.—“On a remarkable instance of Poisoning by means of Lozenges containing Antimony,” by David Page, M.D., Medical Officer of Health, Lancet, vol. i., 1879, p. 699.
808 Brit. Med. Journ., Oct. 14, p. 70.
809 Edin. Med. Journ., 1865.
810 In the first operations of finishing printers’ types, the workmen inhale a metallic dust, which gives rise to effects similar to lead colic; and probably in this case the lead is more active than the associated antimony.
811 Virchow’s Arch. f. path. Anat., Bd. xxv.; also, Centralblatt f. Med. Wissen., No. 23, 1865.
812 Lancet, May 19, 1883.
813 According to Fresenius (Zeitschr. f. anal. Chem., i. 445), a solution which contains 1⁄10000 of its weight of antimony, treated in this way, gives in two minutes a brown stain, and in ten a very notable and strong dark brown film. When in the proportion of 1 to 20,000, the reaction begins to be certain after a quarter of an hour; with greater dilution it requires longer time, 1 to 40,000 giving a doubtful reaction, and 1 to 50,000 not responding at all to this test.
814 See Ernest Jones on “Stibine,” Journ. Chem. Soc., vol. i., 1876.
815 Rieckter, Jahresbericht, 1865, p. 255.
816 The action of salts of cæsium with chloride of antimony might be used as a test for the latter. A salt of cæsium gives a white precipitate with chloride of antimony in concentrated ClH; it contains 30·531 per cent. of antimony, and corresponds to the formula SbCl3CsCl. Chloride of tin acts similarly.—E. Godeffroy, Berichte der deutschen Chem. Gesellschaft, Berlin, 1874.
817 The solution must not be too acid.
818 By adding chloride of tin to a solution of chloride of antimony in sufficient quantity, and passing SO2 through the liquid, the whole of the antimony can be thrown down as sulphide, whilst the tin remains in solution. Thus,—
9SnCl2 + 2SbCl3 + 3SO2 + 12ClH = Sb2S3 + 9SnCl4 + 6OH2.
—Federow, Zeitschrift für Chemie, 1869, p. 16.
819 Zeitschr. f. rationelle Med., vol. xxix. p. 1, 1867.
820 It is unnecessary to state that absence of sulphur is presupposed.